Not much, beyond frame materials. Index shifting came along in 1984, and so did clipless pedals. I think they’re the last two meaningful innovations in recent history.
Headsets have come a long way from threaded to internal. It’s one of those hidden improvements. If pressed to name the most innovative change in the past decade, I’d say it’s the internal headset.
Let’s face it, the bike hasn’t changed much since the diamond frame and gears. You can ride a bike from the 1960s and get the same enjoyment as a bike made yesterday. You sure can’t say that about electronics.
This isn’t a bad thing. The bike’s simplicity is a blessing, not a curse. Marketing does its best to put the “new” into bike equipment, but I don’t think it helps sell bikes. Marketing would do better promoting the joy of riding.
Next time I’ll give my wish list for what engineers can work on. There’s always room for improvement.