I believe we should look for a long term solution. Imagine is mass adoption comes to happen, how can any entity monitor millions or billions of genuine and fake users.

This is a good point, but I think the time between now and this hypothetical future need to be considered too. The norms and practices we have in the present shape what the future is like. And if the platform in the present is more attractive to spammers than it is to legitimate posters then we're unlikely to get to mass adoption (similarly, we also have a problem if whatever anti-spam/abuse ideas are implemented are more burdensome on new users than on spammers).