Having seen this gen play out?
I'm not sure.
At the start of this gen (November 2013) I was so into games that I just bought everything day one, knowing it was my biggest hobby and I didn't wanna miss anything and I wanted to experience all of the technology, controllers, UIs, games and whatever there was to offer. I have an XB1, PS4, Switch and capable PC.
Now I'm far more careful about how I use my limited free time, only a select few games really excite me and I'm more cautious financially because I have investment goals and my own place so bills are a thing.
I'd like to think that going into next gen I could have the restraint to not buy any new system until there is something on one of them that truly has me chomping at the bit to get it, a 'system seller', for lack of a better term.
I think I could be persuaded to fall primarily into either camp, Xbox or PlayStation. Neither are guaranteed day one buys for me without any justification, I think my stance right now is whichever one gives me a very compelling reason to buy it first.
The real differentiation is exclusives. I need to see some kind of mind blowing exclusive game really. Preferably a new franchise so it feels fresh and exciting. A new Halo, Gears, Forza isn't going to do for me, they're played out.