Yes, AR-15's were sold in the 60's, but were very rare in stores.
I would say, in the years since '94, the number of AR-15 type rifles in US civilian hands (yes, even counting neutered rifles), has probably tripled, maybe quadrupled. This is a SWAG.
Many people who said, "One of these days I might like to get an AR-15" saw what was happening and bought as soon as they could before they were totally banned. They liked the first one so much, they bought another, and another. They introduced their friends to these rifles, and they bought.
AR-15's were no longer on the back burner of "nice to have one of these days", but instead, "I MUST have one NOW!"
There are more makes and models, accessories, and such than ever before. There must be 25 grips alone on the market. Then rails, handguards, etc. Amazing!
We have had a wake up call. Those who still ignore it, well, what can you say?