For the military , it was a part of the European arms race that started when the Germans under Bismarck introduced the Dreyse needle-gun in 1841 and began winning battles with it, so there was not too much foot-dragging. Smokeless powder was first a feature of the 1886 Lebel repeating rifle, introduced largely at the direction of Gen. Georges Boulanger. He was leader of the Revanchists, the French nationalists itching for revenge against Germany for the Franco-Prussian War. The lack of smoke gave a clear advantage to soldiers looking for targets. Naturally, Germany knew they would be the targets and followed very soon after with their Model 1888 Rifle , and England soon after with the Lee-Enfield.

In the US, however, there was no particular push to modernize the arsenal, and the single-shot black powder Trapdoor Springfield continued until the introduction of the Krag rifle in 1892. The Trapdoor single-shot breechloading design originated at the Springfield Armory as a cheaper way to convert their enormous stockpile of Civil War muzzle loaders into more modern guns. The Trapdoor was improved over time from the original fragile, case-shredding .58 caliber rimfire design of 1866, but yes, you certainly could say the US was dragging its feet for 26 years.

For sporting gun enthusiasts it was quite uneven. Smokeless powder ammunition ( and, importantly, guns that could take the higher pressure) were coming out by the 1890's, but black powder continued to be popular. One reason was that owners and gunsmiths initially could only buy loaded ammunition, couldn't buy the powder itself for reloading their ammunition, or for experimenting with different loads, wildcat cartridges, etc.. Another reason was linked to the European arms race: it resulted in huge stockpiles of black powder ammunition and rifles, which were then dumped onto the market by modernizing countries and retailed to the public by dealers like Francis Bannerman in New York. Not just the Trapdoor Springfield ( which seems to have become a standard sight for decades, hanging behind the sales counter of every general store with a $1 price tag) but European guns as well- even the Swiss Vetterli would show up in the WV coal field wars during the Battle of Blair Mountain in 1920.

By the way, the National Muzzle-loading Rifle Association was founded in 1932, and continues to this day. Sometimes, nostalgia can be confused with foot-dragging.