It was the norm for there to be a property qualification in order to vote. In England it was the "rate-payers" who had land- though, since the requirement was set for a freehold worth forty shillings, in 1430, over time more began to qualify as a result of inflation.

Similar qualifications existed in the Thirteen Colonies. Maryland, for example, required 50 acres of land or 40 pounds of personal property. 40 pounds would be a year's wages for a skilled craftsman doing well. Not a small amount, and given the cost of running an election campaign it is not too surprising that the men in the legislatures of the colonies were elected from the wealthier elites.

Those colonial governments had to re-configure themselves once the War for Independence was under way. The royal governors were out, and some executive needed to take their place. As a result, there were a lot of state constitutions written, and some of those were pretty progressive, Pennsylvania's especially. Four states dropped the property qualifications, and a number more lowered them a lot.

However, the elites that were in control during the War were also in control after the War, and once that War was over they did indeed begin to worry about whether there might be mob rule. John Adams, especially, and George Washington got very excited about whether Shays' Rebellion in Massachusetts might be the start of a popular revolt- Shays and his followers were veterans of the War, had been paid in worthless Continental currency, and there were possibly many discontented like them who would pick up their muskets. So, there was an amending of the war time constitutions in some of the states, and property qualifications mostly returned. But the US Constitution allowed states to set their own rules for voting, and pretty quickly after 1787 there were states that removed property qualifications- Kentucky, Vermont, New Hampshire, Georgia, and Delaware. But some states held on to property requirements well into the 1800's- New York, for example, which had a landed aristocracy similar to England's.

As for why the situation changed, de Toqueville would point out in his 1835 book Democracy in America, "Once a people begins to interfere with the voting qualification, one can be sure that sooner or later it will abolish it altogether.". There was no royal authority , or titled aristocracy in charge to prevent it, so it happened. But when de Toqueville was writing his book, the Great Reform Bill in England had also done away with property qualifications ...so even there, it seemed like a relic of the past.