Everything full-auto was a missed deal.
Other than Full Auto, there isn't much that I feel I've missed out on. And, I'm just glad to have bought the one full-auto gun that I have when I did!
I still want a Sig AMT - but even 15 years ago folks were trying to get $4,000 them. Now, they want $6,500+.
I do regret not buying an FN FAL sear-cut when I could get one for about $2,000.