I don’t think I’ve ever seen so much damned hand wringing over something so inconsequential. But I must say the line of ‘why can’t Paizo just abandon its own silly game and produce some stuff for the system I like’ is kind of irrelevant...
To further put this into context, Paizo is just a teeny tiny company in the world.
Remember they were just printing magazines and running an online game store like MiniatureMarket or TrollandToad - you can still buy things like Ticket to Ride or minis from Paizo, it's just they quote 38 days to get it to you so I imagine that part of their business has fallen materially as their CEO stepped down and the pandemic hit.
As a teeny tiny company,
it's about the human beings - the creative people who worked there. Without those people, those individuals, Paizo is just a word, a limited liability corporation, and a fairly laggy website.
So when asking, why isn't Paizo making great new creative content like you were used to them making (Rise of Runelords, Crimson Throne, Kingmaker, Carrion Crown, etc) and making it for 5E?
The answer is...
"they" (the Paizo you used to know) are absolutely doing that.
When you get an RPG product you love, open the cover to see who you can thank for bringing that to light. It's not about Paizo LLC, but about the creative individuals whose brains were available during the brief schism of the 3E->4E transition and willing to write content for a 3E-compatible ruleset.
The Golden Era of Paizo, if you look at the authors, was built on the creative efforts of - Pett, Bauer, Logue, Greer, Vaughan, Schneider, Kortes, Leati, Hitchcock, Spicer, Hodge, Reynolds, Sutter, Frasier and even Radney-MacFarland (who was there briefly for the launch of PF2E). Nearly everyone from that era has left "Paizo LLC" and if they are still writing, they are, at large, producing their work for 5E and elsewhere. It's really just Jacobs and Bulmahn left from the magazine days trying to hold the ship together.
So, you've got this online store where not only has the CEO left as of 2018, but all these creative people who were great at their jobs. They have this legacy product line in Pathfinder (and Starfinder to a certain extent) where they have just enough demand to justify a nominal expense to develop content. With that small budget, we see books printed in China, and organized play fans who are largely inexperienced taking their first crack at authoring content alongside ever-rising price increases on the products.
If your real desire is to see Paizo LLC produce 5e adventures, ask yourself
who you want writing and illustrating those. Chances are they are already doing so, or would be receptive if you approached them to encourage them to do so.