I'm 50% on them showing something this year... I think they will probably release 1 year after launch of the console, though. Any more than that, and they know they will lose momentum.
They did say that the console would be backward compatible with original PSVR, but that in itself is a mystery. I can maybe see new games on PS5 being compatible with both headets for a while, but what spec do the devs develop for before PSVR2 launches? Do they just wait for new hardware? Even 1st gen PSVR games still have to be one of the certified PS4 BC games in the first place. There are still a lot of unanswered questions on that. Ironically, Xbox would have been able to make an easier transition, given the 100% XB1 compatibility in the first place. But then, they choose to just sit back and watch the revolution from the sidelines.
Anyway, I understand 100% why launching PSVR2 at the same time as PS5 would be a logistical nightmare. I have a V1 PSVR that doesn't even have HDR passthrough. I have a workaround, but it's still stupid. I blame them launching the Pro at nearly the same time as PSVR as a huge reason for not focusing on either enough to make them 100% compatible with one another's features.
On that note, you can see that the controller is already designed for inside-out tracking, given that the lights are on top. I'm thinking that PSVR2 must be pretty far in development by now. I say that it's more of a waiting game of logistics at this point, but they can use an extra year to refine it, too.
All in all, they have nothing to lose by showing it off a year ahead of time...except they can't show too much, and let both Microsoft and Oculus know everything they are doing.