It's very likely that if the said small channels are indeed too small to be allowed to monetize, then they would fall under the not profitable accounts even if they were allowed to monetize.
It might take 6 months or even a year+ of dedicated uploading to meet those guidelines for most content (unless it's a really popular / trending niche like a new game, etc.).
If Youtube starts banning those accounts then they are effectively not allowing anyone else to join their platform because they would be terminated before they have a chance to get popular enough to enable ads so that Youtube can make money.
That's a huge if - one that Youtube probably is not going to enforce on new customers. The same principle applies to most businesses I know - a new account/client has X months to be profitable until they get dropped.
On the flip side, i've often stumbled (in the days where I was parsing youtube for side projects) on projects with hours long videos with 3 views - for years. My best guess would be that those accounts / uploads are what youtube is targeting, not preventing their new account sign up / new DAU drop.