Both. Coordination is so difficult, we have no good voting mechanism aside from "core merged the pr" (terrible), hashrate, and UASF (unpredictable, dangerous). And also nobody wants to "try something new" on a monetary network storing the world's savings. But eventually we have to try new things or BTC will be outcompeted by chains that do. We can say "let other chains experiment, BTC will take the best features at the finish line and integrate them into BTC" but that hasn't been true for like a decade.

But we all agree someone should be able to sell their BTC to buy fiat, shit coins, or whatever else they want. Drivechains just build that into the protocol, you can shuttle your BTC at your own risk onto a sidechain and back.

Experiments are needed, altcoins will exist, with drivechains they are still tied to BTC and still fund Bitcoins security budget. All the while giving the user the choice of where to park their coins and letting the market decide gradually one tx at a time instead of during a dramatic fork event.