I disagree.
The big email players are accepting mail from universities and large companies with misconfigured email servers. If you use the same rules that Google and Microsoft use to refuse emails, you will be bouncing emails from valid domains. If you don't apply them, you end up accepting spam. The big players are able to deal with the spam using specialised teams and I suspect advanced algos including machine learning.
IF the big players applied their famous rules to everybody equally, everybody, including universities, big companies etc... Would quickly configure thier mail servers properly, which WOULD reduce spam, possibly eliminate it.
Being able to keep inboxes fairly free of spam in a world full of spammers is what distinguis big email providers and enable them to sell their services.