This is a key point.
If you look at people, each of them have multiple different “personas” throughout the day/week/etc.[0]
Some of them, sometimes, are builders or content creators.
Some of them, sometimes, are conscientious consumers, looking to stretch their understanding or themselves and think hard about something that they are consuming.
But all of them, sometimes, are Marl.
There will always be a way to find more Marls to add to your user pool because Marl is the basest human need for a steady effortless dopamine drip. Just about everyone has some amount of time that they spend as Marl, so there is an almost limitless pool of Marl time to pull new users from.
I’m trying to find some way to say that this isn’t what you actually want, but I’m struggling. If you are making a product for everyone, Marl is the only persona that is in everyone, so you should probably target Marl.
However, if you are trying to build a product for a more constrained persona, you should probably be careful of using metrics that measure Marls. Because there are so many of them (even your users with other personas are sometimes Marls!) if you aren’t really careful, you will enshitify your product as you continue your A/B testing gradient descent into a user base of Marls, without anyone you were trying to get — even if you don’t loose your content creators and conscientious consumers, you have converted them into Marls, and lost what you were trying to achieve.
Enshitification is the conversion of your target user from any other kind of persona, to Marls.
[0] there are other personas, these were that the ones that immediately came to mind.