There are two parts to this. First, the pro-slavery arguments were never confined only to the economic loss of owning people as property. I have touched on this subject in previous answers on this sub here and here. Just to reiterate some of the other arguments made against abolition: it would usher in a race war, it would bring down wages of white people who now would have to compete with formerly enslaved black people for jobs and who would work cheaper, the black South would align politically with the North against the white South so that the white South would no longer have any political power, it would usher in a mixed race society and "degrade" the white South to the same level as formerly enslaved black people, and so on. None of these other arguments were addressed simply by the federal government offering monetary restitution to slaveholders. So an attempt to emancipate people and pay the slaveholders the monetary value in human property was never enough to gain the support needed to make abolition a reality, which helps explain why it never happened.

The other part of the answer is: there absolutely were attempts and suggestions to enact a "compensated emancipation" policy, as it was then called. Before Lincoln, no previous president ever really made the suggestion publicly because either A) they didn't believe in abolition, or B) they believed it would inflame Southern tensions against the federal government when the prevailing wisdom from the 1830s on was to appease the South on the slavery issue, and make further concessions and pro-slavery guarantees at the federal level. As such, Lincoln was the first to publicly support such a policy, and tried to advance it several times early during his presidency.

In November 1861, Lincoln began working with Rep. George P. Fisher of Delaware on the possibility of getting a "Compensated Emancipation" plan introduced in that state's statehouse, as a trial balloon to try to get other border states to join in. Lincoln drafted the proposed legislation himself, on November 26, 1861, but Fisher's efforts to get it to a vote in Delaware over the ensuing months did not go anywhere.

Undeterred, on March 6, 1862, Lincoln issued a proposal in a Special Message to Congress, requesting the passage of a bill to allow the federal government to pay for any Compensated Emancipation scheme passed by any state, in hopes of getting the loyal slave states to move forward with such a plan. The loyal slave states actually had a conference with Lincoln shortly thereafter, but only Maryland actually debated it in their statehouse. It did not have enough support and did not even come to a vote.

The only place "compensated emancipation" ever became law was in Washington, D.C. The Republicans in Congress had the votes to pass the District Emancipation Act, a law that banned slavery in the District of Columbia, which Lincoln signed into law on April 16, 1862. Under the law, all slaveholders were compensated with $300 for every enslaved person freed under the law. However, many D.C. slaveholders instead just left D.C. for Maryland or Virginia, where the enslaved people would not be freed.

Going back much earlier, there were sometimes suggestions at the state level for "compensated emancipation". Kentucky debated it during a state constitutional convention in 1849-50, but the overwhelming majority of delegates were against it, so it never came to a vote.

Even earlier, Virginia had debated both "gradual emancipation" and "compensated emancipation" in their statehouse in January 1832 in response to the Nat Turner Rebellion. While there were many proponents of these plans, they were still not enough to overcome the pro-slavery supermajority. The result was not only did emancipation (compensated or otherwise) never come to a formal vote, but they voted to ban any further discussion of emancipation in the state.

The bottom line is, through 1862, there were efforts to enact statewide "compensated emancipation" laws. Debates happened at the state level, but it only first happened at the federal level under Lincoln's early presidency. Abraham Lincoln delivered a Special Message To Congress in favor of such plans, with federal funding. But the laws never got much traction. Instead, by the end of 1862, Lincoln had gone ahead with the Emancipation Proclamation, by which time many Republicans were already publicly arguing for an "immediate emancipation" policy, that Confederates had lost any right to property in human beings the moment they took up arms against the U.S. government. By 1864, the political climate had changed, so that even in loyal slave states like Maryland and Missouri, they had begun to enact uncompensated "immediate emancipation" laws before the 13th Amendment was passed.

Earlier than 1861, no U.S. President ever made the suggestion publicly at the federal level for fear of igniting war or exacerbating existing tensions. And at the state level, whenever it had been suggested, it went nowhere. Lincoln was the first to really advocate for it, although Millard Fillmore had also written a lengthy passage in one of his State of the Union addresses that would have combined far-off compensated emancipation with deportation to Africa ("African colonization") of both freed and freeborn black Americans as the path forward. But it was viewed by his advisors as such a political dead end that his plan was edited out of the final speech.

And to put it in perspective, even Fillmore's exceedingly conservative approach was deemed too controversial to be made public. If you read it, Fillmore simply states that the federal government should be willing to support compensation and "colonization" through federal funding, but that actual emancipation and abolition was none of the federal government's business, and could and should only be done voluntarily by the individual states. He just wanted to make such a plan more attractive to the slave states than it currently (in 1852) was. And even then, he predicted that it could only be accomplished through "the work of many years, not to say centuries". Clearly, the issue was so toxic that even making a suggestion of "compensated emancipation" was seen as killing your political career. At least, until the Republican Party came into being, particularly after the start of the Civil War.

EDIT: Proofreading, clarity, and an additional link.

Hey there,

Just to let you know, your question is fine, and we're letting it stand. However, you should be aware that questions framed as 'Why didn't X do Y' relatively often don't get an answer that meets our standards (in our experience as moderators). There are a few reasons for this. Firstly, it often can be difficult to prove the counterfactual: historians know much more about what happened than what might have happened. Secondly, 'why didn't X do Y' questions are sometimes phrased in an ahistorical way. It's worth remembering that people in the past couldn't see into the future, and they generally didn't have all the information we now have about their situations; things that look obvious now didn't necessarily look that way at the time.

If you end up not getting a response after a day or two, consider asking a new question focusing instead on why what happened did happen (rather than why what didn't happen didn't happen) - this kind of question is more likely to get a response in our experience. Hope this helps!