I have had enough experience with unsubscribe on spam that I have to wonder what your figures are for "working well enough". They don't work enough for me. It is also a well-known assumption that using unsubscribe on a bit of spam only confirms that the sender has found a working address and those sell for more on the spammer's email address market.

I also don't understand why "marketers" want to put stuff in my email inbox or anything else I use to receive real communications that I just don't want.