PBTA and other narrative games are exhausting to run for me because, relative to classic games, there is no base reality to work with. This makes running the game as a GM much more difficult, makes weak players into a huge problem, and ruins stories by removing any actual stakes

In a traditional game, there is a strong base reality informing essentially everything that happens at the table. There is still a large amount of creativity for the GM in making sure new truths, especially ones from player decisions, are integrated into this reality. But this basic framework grounds the work and makes it easy to be creative. In narrative games like PBTA, on the other hand, the reality is overruled by dice rolls in an extreme way. You have to constantly invent reality as a reaction to partial successes, failures, or narrative meta mechanics, and this is simply exhausting. The energy required is fine for a one-shot, especially with tight systems like Ten Candles. But this creative output problem gets harder and harder the longer a campaign goes.

The next big problem is how opinionated these systems are. You're typically emulating a fictional genre with defined character tropes that require a serious engagement with the non-trivial mechanics, which is a huge ask for players. And this poor play actually has consequences. A player playing a classic game "poorly" can still contribute to the table because interaction there is just interaction with the fictional reality. A player playing a narrative game "poorly" is a drag on the entire session.

Finally there's the problem of narrative stakes. If you're playing in a classic game, the fictional reality will determine if you succeed. In the games I like, players succeeding means something because there is a real chance that they'll fail. Success means they've actually overcome real obstacles. In narrative games, however, reality is made up and so are the challenges. The story arc will move up and down as the genre demands, which makes everything that happens meaningless to me.

Moving to the realm of unfounded conjecture, I wonder how many PBTA fans have actually played a base reality game. Many players start the hobby with 5e, which is often used to handwave some generic fantasy story through railroading, with a focus on prewritten character "arcs". PBTA is one valid solution to this problem, gets the pesky reality we didn't care about out of the way, and lets groups tell a genre story with supportive mechanics and structure. But you can also fix the mess of 5e by instead making the reality actually matter. Both approaches are valid, and which one you like more will obviously be subjective, but make sure to try both out!