Its because they're garbage. When a CRT from the mid 80's powers on, warms its tube up faster and switches inputs quicker than a modern TV, something is very wrong.

I'm pretty sure the NAND is degrading in my 2015 Sony Bravia, its bordering on unusable with its hangs, jitters and crashes.

I barely trust any manufacturer to produce consumer grade goods that actually do their job properly, the best way to get more stuff working right is to narrow the featureset and hope that they're not completely incompetent.