Nest Hub was $99, and is now perpetually out of stock. AFAICT it's discontinued. Which is strange, and a shame, because it's a great product. People are paying similar prices for digital picture frames with a cloud service, which the nest hub can do with a little bit of config, and a bunch more.
Its the same price as an Apple TV 4K, 4th gen. Which is twice the price of the previous generation.
RAMpocalypse sucks.
Nest hub also likely does little locally and sends everything to Google.
You seem to be comparing that to a full tablet running home assistant ?
That would be a whole different category of device and surely not at 300 USD.