

Unfortunately, they haven’t figured out a way to get gorilla glass to bend and not shatter so the current plastic screen is way too weak and a fingernail can scratch it. Not good for a $1500+ device.
A $100 Motorola Moto G Play has a 6.5 inch screen. To get a foldable big enough to double the screen area would cost $1400 more. Most people couldn’t afford that, so the budget phone is the best price/screensize compromise. The foldable still get more easily scratched than the $100 phone which just makes foldables very bad.
Carriers also has the final say on your update, and they are the ones signing it.
Updates go from: Google —> OEM —> Carrier. Extra delay for critical patches for security vulnerbilities. Hackers are very happy about this