@Wind_FURY, I found your quote at http://www.drivechain.info/, by the way.

I watched the youtube video and the guy was mentioning how each sidechain has a reward attached to it that they didn't think out through. I don't know how frequently this activity happens in the bitcoin development ecosystem but it's common for a lot of altcoin devs to not think through very important parts of the system through which reflects in the stability of the altcoin.

One problem I can think of right off the bat is what will happen to sidechains that scamcoins are hosted on after their developers abandon maintenance of their sidechain. I think that would be a waste of space.

But I think a much more important problem is that devs can't force everyone to use drivechains due to the decentralized model of bitcoin, by pushing a new bitcoin core release. Still, lots of people/services aren't using native segwit addresses, in some cases they are even using legacy addresses. But that's a different topic.

Now I'm not claiming to know anything about drivechains, but nothing is stopping someone from hard-forking bitcoin even if drivechains were in place. I don't think drivechains can interfere with layer-1 activity which is where the hardfork takes place.