Adblock won't block the "subscribe for 2 free articles" popups.

Of course it will. At least the second time, after you tell it that '.popup-subscribe-modal' should never be seen again.

It's not '.popup-subscribe-modal', it's often a random string spit out at build time that changes with every deployment.

True, but then you can search for specific strings in the div, etc. Maybe not worth it for something you visit occasionally, but well worth it for a website you see often.

Or even with every page reload.

the whole point of the article is that browsers should try to block popups that don't literally open a new window too. Although I doubt it's really feasible without doing it on a one-by-one basis like ad blockers

Of course, I don't disagree with you. But OP tried to refute the fact in their parent comment that using adblock is generally better than relying on browser's pop-up blocking. However, adblock does no worse than pop-up blocking in the specific case of non-window pop-ups, making it irrelevant in the context.

And I agree that these types of ads remain a hard to solve problem today.