Unless the spammers simply run remove the extra part from the address. A better way is to get your own domain and use a different alias for each service.
More importantly, legit services that are on the spammy side (or have broken unsubscribe links) will absolutely never remove it.
Back a few years when Ameritrade had a bunch of its user's emails sold to spammers, I just changed my email on the ameritrade website and started blocking my +ameritrade address. It worked like a charm.