I've never understood the draw to the in seat entertainment. You pay extra for something that you probably already have available in other ways. An ipad in the kids hands or with a holder on the back of the seat does the same thing, but is also usable in your house, hotel, or where ever you are on vacation.... plus is infinitely cheaper to repair/replace. Technology changes quickly, so I'd rather the individual device get outdated than something that is permanently and expensively mounted in my vehicle that ultimately just becomes clutter in the vehicle over time.
I actually got excited when the 2021 GLC SR didn't force me into having the built in entertainment system. My 2005 GC has rear entertainment in it and it basically just takes up room now. There's the flip down screen that blocks my rearview mirror, the headphones are some kind of fm transmitting technology that is long outdated compared to bluetooth, the DVD player just consumes room .. plus we have to have DVDs in cases in the car?
I realize 2005 is a long time ago, but the premise still stands. Tech gets outdated quickly as new and better products are created. It all looks shiny now, but in a couple years you'll wish it had XYZ feature, but it would be WAY to expensive to replace it, so you'll buy the portable version (like an iPad) instead and relegate the expensive in car system to collect dust and take up valuable space in the vehicle as you're now affectively transporting two entertainment systems everywhere for no reason.
</end rant>