That wouldn’t change the security assumptions on the base layer. Of course if you break this assumption, all sort of attacks are possible.
Discussion
It does change the security assumptions. Currently reorgs do not help miners, ever, at all. They are rare and an unfortunate result of the decentralization. If you add those shitcoin chains where value is being passed around in sidechains then you can potentially incentivize miners to intentionally reorg the base layer. That would be very bad.
But again I really suggest you study more and talk less because you do not know enough about what you're discussing to have such strong opinions, both of covenants and drivechains.
Since you seem to have studied #Bitcoin a lot more than me, maybe you can point me to a resource that goes in depth with the particular risk that you’re describing. I haven’t seen any such analysis but if it’s such a concern, I’m sure the critics have posted a write-up on it.