That's not an argument of quality at all. Just an admission of wanting to go with the status quo for the sake of it.
You already have sunk costs, and have to spend WAY more money, by going along with 2024 D&D. Your older D&D books are invalidated and you now have to buy many more to keep up.
So what actually is there to be "invested" in here, that can't instead be done with a better product? It's already a new ruleset that has to be adopted. You're simply choosing to adopt the rules of a game that happens to be from the same company. It's like if a restaurant started selling chicken nuggets instead hamburgers, while deleting all the coupons you received from buying hamburgers, and you blindly insisting the chicken nuggets must be the best thing to eat, since you formerly bought hamburgers there.
This is you putting words in someone's mouth, yet again. Also, people don't know what they like best if they don't experience alternatives. If people truly feel D&D is the best, having come to that conclusion from playing many other games, then sure. But it's frequently the case that people have only experienced a sliver of what exists.
I'd also posit that most people have a bunch of things they would ideally like to change about D&D. Supporting another game will result in a higher chance of those desires being fulfilled. Like, you can talk directly with the person making DC20, ditto for various other games. Whereas with D&D? Fat chance they listen to your advice. They can't even design "conjure minor elementals" properly.
D&D doesn't have less rules.
Look at how it plays, not a PDF. There are games to watch and for me the combat there, with the system not being in its final form yet and people still needing to spend some time getting acquainted with the rules, was more kinetic and interesting and engaging than in most "professional" 5E D&D games, a system that's been given many years for people to learn and yet is still a source of constant confusion for "professional" players.