Anyway the txsigops limit is enforced by nodes relaying txes, and the blocksigops is enforced by miners. Evil miner can exceed the limit if he wants. It's only a 'bandaid' to the problem.
but mallicious users are not going to move funds to segwit keys and intentionally disarm themselves.. so segwit doesnt 'fix' it
segwit doesnt even force users to move funds to segwit keys either. users can still use native keys.. so segwit doesnt 'fix' it