The term "Latin mass" confuses two distinct aspects. Colloquially it refers to celebrating the Tridentine Mass in Latin. But the Tridentine Mass was already celebrated in the vernacular years before Vatican II, though it was optional and I don't know how widespread it was. The Vatican II reformed mass was expected to use the vernacular in most parts, but it can also be given in Latin, and Latin is the canonical form against which translations are made.

I've been to a Latin mass a couple of times, specifically a sung (aka high) Latin mass. I see why so many people prefer it. But the Novus Ordo can also be sung. Latin masses also tend to use incense, etc, which also used to be more common in the Norvus Ordo. The real division is between parishes and priests with the energy to put into the mass, versus those that fall into the habit of doing the bare minimum. The "Latin mass" just happens to be a convenient mechanism that bifurcates the two groups.

Relatedly, I read a argument somewhere that the current state can be traced back to the proliferation of Irish priests. In Ireland the low (unsung) Latin mass had apparently been for centuries the predominate form even on Sundays. I'm not sure how accurate that is, but reading various sources it does seem that in various parts of the world the sung mass had already been in a long decline at least since the 1800s. And I think the Norvus Ordo was intended to simplify things in the hopes of reviving the energy in the mass, but instead it just created a lower floor.

I've heard the same re. the Irish.

Regarding the Novus Ordo, I believe that the key document from Vatican II (Sacrosanctum Concilium) still preferred Latin as the dominant language in liturgy, while readings etc. stayed in the vernacular, but clearly that is not what happened.

There's been an uptick in numbers for Tridentine Rite, so tides might shift back as Catholics realize the wealth of their liturgical tradition.