Aside from marketshare, the sheer mindshare of PS4 is insane.
For a system that IMO has the weakest controller and middling to straight up bad consumer policy (the crossplay debacle and communication surrounding it, that ERA member whose account kept getting stolen, not being able to change usernames until recently, charging $100 for a mini console instead of supporting their existing PlayStation Classics software), people just cannot get enough. The lead is incredible.
PlayStation is synonymous with gaming for just about everyone now.
You list some super nitpicky issues for most I think.. I mean, listing one user's issues?
Even the bc issue, and the Xplay you list, have largely been non issues for the casual players out there.
The #1 issues listed for PSN usage (name change, external hard drive) have been adressed, and even the Xplay one is being delt with.
Sony might be slow, but they have shown they are listening (and let's not forget they actually were the ones championning Xplay with pc, and still to this day champion actually free F2P with no sub needed).
As far as I'm concerned, the PS network is more reliable than it's ever been in the past, the DS4 is a massive improvement over the DS3 and its features even make it a PC user's choice in many cases, PSVR is great and affordable on what is essentially a $199 machine, and most importantly the games, both 3rd party and exclusives, have been incredible and coming at a steady pace.
5 years in, and I'm playing things like HZD and RDR2 at 1080p30 and loving it.
I honestly think the PS4 is -the- current gaming machine, powerful (for its price), affordable and with a vast and deep library, so the market's choice seems natural to me.
Sony's international support and presence also of course backs those advantages.