Keeping bitcoin promise as far as it is possible and pushing to the limits, it is the point.
Disabling OP_CHECKSIG means destroying wallets that do not follow our orders, It wasn't part of the code, the contract bitcoin has "signed" with the user. You can't just show up with a new address scheme ordering people to migrate. They have a right not to follow, it is constitutional.
there is a dilemma here. firstly, this scheme of yours involves too much trust---in miners to privately mine transactions without stealing and in p2pkh holders to properly secure their coins. they are theoretically a threat to us all.
secondly, bitcoin's economic design implies
what satoshi said explicitly---"Lost coins only make everyone else's coins worth slightly more. Think of it as a donation to everyone."
so it becomes a point of contention. whose interests are more important---
a. people who want to keep their outputs in vulnerable format for eternity (despite safe alternatives) and who will require trusted/centralized solutions to spend them, or
b. the rest of the bitcoin economy?
even if we table the discussion about needless complexity, bitcoin holders will not be interested in your way. they will prefer a predictable outcome that more reliably ensures that bitcoin's value remains intact.