You're absolutely right.
I liked the Atari 2600+ when I received it, only a few carts wouldn't work on stock firmware.
I then upgraded to the latest experimental firmware and that made it worse - the ones not working before still don't work and several carts that did play fine before now refuse to load or need several attempts to even recognize that there is a cart plugged in at all.
I completely lost interested by now and the unit is collecting dust which is a real shame.