Not having to login to Twitter is a great feature. I don't have a Twitter account, but often see posts linked elsewhere, and hated getting hit to login each time.
How? By having different requirements and implementing another solution? Look at the guy behind YouTube purge tool. One guy accomplished more than YouTube have done for years. Why? No one knows but it's definitely not because lack of resources. I've definitely seen less spam during the last months.
No, he's talking about the very recent spam explosion in the YT comments, and how a dude manged to build an actual counter to that when YT hasn't really done anything on that front. I guess spam decreased since the peak of 3 months ago, but it's still a massive problem. And again, this is in the past few months, and has nothing to do with the improvements to the yt comment algo changes of the past few years.