Spammy accounts? Why?

Hello everyone. First, let me tell you that I joined Medium a couple of days ago and I have a question that I hope some of the more experienced users of the site can answer.

What about all accounts created to post one or two articles without substance, with the intention of promoting a product?

I wonder if the administrators of the site doing actively something to reduce their number or is it not too big of a problem here?

I know spam is a worldwide problem, and almost no place online is safe of it, but I do have to wonder, what´s the interest of trying to spam a community like Medium? Maybe the large user base? Perhaps how often is new content uploaded here? I wonder this, mostly because I see this website as a more mature and classier place than the ones that spammers most often visit online.

And another question I have is how long do those accounts last online? A couple of hours or most are still standing?

And the most important thing. What we can do as a community to try to stop those spam accounts and the quick spreading of their posts? Kinda relevant in those pandemic times, if you ask me.