I think I have to disagree with the assertion that Standard was improved by War of the Spark and friends... but that might just be because I can't look at any of the top decks from ELD standard without vomiting in my mouth a little.
I didn't say Standard was improved by these sets, just that more people started playing when they came into being.
I live in Minnesota, and every spring set they do a big prerelease tournament in the Rotunda at the Mall of America. I've been to a few of these, they're very fun because you get to meet people from all over the state (and in some cases the country) who play Magic. The two most attended prereleases while I've been going there were War of the Spark and Dragons of Tarkir. I remember showing up to the War of the Spark prerelease to see almost the entire rotunda filled with people ready to play Magic. It was really heartening to see a high turnout because even just a couple of years earlier less than half the space was being used. Even Amonkhet, which was probably the best set released after Khans but before Guilds of Ravnica, barely managed to fill half the room.
Ever since Guilds of Ravnica (and
especially War of the Spark), more people have been buying and playing Magic than they were in previous years. I'm not going to sit here and say standard was perfect during Okotober or the late Eldraine era, (although I think both of those formats were preferable to energy hell or copycat.format), but by that point standard was playing a diminished role in Magic's ecosystem as a whole so it's impact wasn't as important.
I also have the suspicion that a lot of the "popularity" of powerful sets is a result of Constructed players feeling the need to get their hands on cards from that set to compete in their format of choice, and not, say, because that set producing a good limited format (though it that could also be the case).
This isn't actually true. Kaldheim broke the sales record despite being one of the weakest sets in the past couple of years. Despite not having anything resembling a format staple (at least until Standard rotated), it ended up outselling Ikoria. I don't think an unremarkable competitive set would have managed to outsell one of the most broken sets ever if sales were being driven by constructed outliers. People just liked the Viking theme and the set had some fun cards and a unique limited environment. Simply put, people wanted to play with Kaldheim. Now, of course, having a set with constructed applications does help sales. Kamigawa, Neon Dynasty also took the sales record, unseating Kaldheim. While it didn't have many constructed staples for eternal formats (other than Boseiju), it did bring along a bunch of really cool cards that could fit into Modern or Legacy decks if one wanted. Likewise, the set was full of fun cards commander players wanted.
Now, we can argue about whether or not a set adding a ton of playable cards to an eternal format (instead of just adding one or two outliers, like Fatal Push and the like) is a good thing... but that's something that needs to be kept in mind when evaluating sets.
I don't think there's a clean answer to that question and that's not even point of this discussion tbh.