It means prosperity in the sense that the manufacturer is taking you to the cleaners by eliminating smaller low-end and mid-range products to funnel you into higher margin "big" things, for both cars and phones.
SUVs being pushed so aggressively the US is because the margins are better and the segment is eternally protected by the Chicken Tax. The insane CAFE leniency for lardassed SUVs/"light trucks" is fought for tooth and nail because the margins on SUVs (especially full-size ones) are crazy.
Same thing happened with phones. Remember when a thousand dollar phone was stupid? Now that's what shit gets developed on, tested on, etc. It's just normal, and that's great for people who make phones.
Not enough modest people exist to really make an impact in sales numbers and even if they did, they don't really drive any more sales. I know multiple people that are very well off, money in the bank, with a nice house, multiple very nice (enthusiast) cars, that just don't give off the same FOMO effect as somebody in a shitload of debt living in a McMansion driving around a shiny new Navigator.
Old (er) people spend a lot of money. Old(er) people want larger screens and bigger cars because they're easier to overcome physical issues (sight and dexterity).
Still blows my mind that this is like that in countries that didn't go through a 70-year period of socialism.
Anyway, old people don't buy smartphones as much, at least from my observations. They still only use a phone for calls, so why bother? There exist dumb phones with large buttons and simple large UIs specifically for older people.
The same model of SUV is always bigger as time goes on, and there seems to be no small pickups anymore.
I've always wondered if modest people buy used devices and cars, and don't have a say in what new ones are like.