So PS4 can run games off external, ok. Point still stands, they can have you transfer data back and forth between internal and external.
Point doesn't stand, at all. You don't need to transfer games in order to run them, as you claimed. You run it from wherever it was installed to. That requires either loading directly (as with PS4 and X1) or caching. Caching requires a large amount of internal memory to be reserved, as games are
already exceeding 100GB and still growing.
I'm fine with caching, as for me an infrequently and predicatable penalty is worth it for the gameplay experiences it can offer.
But you can't expect people to have to buy external SSDs in order to go beyond what is already a paltry and almost unusable "480GB" drive. All of the PS4 / Xbox 1 owners I know already have 1 or 2 TB USB driven HDDs supplementing their clogged up systems. And yeah, for most of them it's 2TB.
Switch is also a home console, so eternal Nintendo critics aside they're getting people to pony up for external storage and the system sells like hot cakes.
Nintendo have no other option but to use
only solid state. Nintendo Switch games run (mostly) from the carts they were bought on, and don't need installing. Nintendo Switch games are relatively small. Nintendo aren't so heavily into DD. Nintendo games aren't available on a competitors platform. Nintendo have no direct competitor in the niche they have identified and conquered.
Just because Nintendo have succeeded with these limitations (this time) doesn't mean these limitations will not be a factor for vastly larger games, with vastly more DD activity, in a fight with more direct competition.
If the software and hardware is good, people will buy more storage.
So people limit their software and hardware purchases because of cost considerations, but somehow, the finances to purchase additional storage are not even a factor!
Bollocks.
Money is finite. It you want to buy games but can't because you have to spend four times the value of that game on external storage first, then software sales suffer.
The time of solid state consoles will come, but not in 2019 with a 500GB PS5.