The question is, Why are they running out of air?
The two main reasons (assuming they ever held air at all) is bad rim tape and bad valve sealing---the valve tot eh rim, not the valve core or head (though I would check both.)
I double tape my rims so I know they are fine,. When I had tubeless tires losing air, therefore, I knew it must be the valve. Apparently cranking down too hard on the valve doesn't seal them better, but causes leaks, through ripping the tape or damaging the gasket or however ..... I replaced the valve, installed it more carefully, inflated the tire with a hand pump, added sealant (it stayed seated) and it has been holding up fine since.
They haven't all been that easy but i have to think that as I improve my technique they might.
Again ... if the rest of the bike is worth it, you can just drain the tires and add tubes and never think about it again.