Well, you have to consider that some people become annoyed by changing their tech too often and that with the amount of electrical and plastic garbage accumulating around the world that decisions will be taken in regards to lifetime of consumer tech. Just look in the US where Apple is not obliged to make their phones repair friendly and that planned obsolescence is beginning to make headlines.
With the PS2 lasting that long, Sony should be proud of it, and even if the PS3 had shorter lifespan, it is still remarquable.
With Ps4 and the recent ps4 Pro I was baffled as (for me) I did feel i bought my PS4 not so long ago and everything is still playing fine, so why change ?
I would like however a PS where its internals are swappable, but this would be more of a PC than a PS.
As for PS Now, it seems a good idea, but with all titles we have to buy, at the premium prices we have to do (if we are not patient, and on what studios are counting on), not sure it is a viable business decision, even if appealing.