Good theory, but I think you're wrong. That's not what's hurting Microsoft - Sony did the same thing, with rumors of the "Neo" appearing shortly after the console itself launched. And yet the PS4 still sold quite well from day one.
What hurt the Xb1 is that it's demonstrably weaker than the PS4, but cost significantly more at launch ($500 compared to $400). Most games are available on both, so the natural inclination is to go with the cheaper and more powerful console. With a wide library of shared games, there's lots of direct comparisons to make, and even before they launched, it was easy to tell the PS4 would be more powerful. That gave the PS4 a very strong advantage during the first year or two.
Even now, they only have price-parity, with both having an entry price around $250-$300. But more people already have a PS4, making that the more attractive option both for multiplayer gaming (if all your friends are on PS4, you'd want one too) and for the larger percentage of third-party exclusive titles (it's nowhere near as big a deal as it once was, since porting is so easy, but there's still some studios that are deciding to skip the Xb1 because the audience is smaller). And it seems to me (as a non-Xb1, non-PS4 gamer) that Sony's shoveling the money from their console sales into more first-party games, giving it a still stronger library, which is ultimately what every gamer cares about.
Microsoft doesn't have a lot of options for coming back from this, just as the PS3 struggled to come back from the Xb360's early lead and the XbC never came close to the PS2. They could make the Scorpio be *substantially* more powerful than the PS4 Pro, making it more future-proof and maybe able to handle 4K/VR better. They could slash the price, and hope to catch up that way, but that's a risky move. They could pin it on VR or AR, but that's riskier still. They could double-down on their cross-play with PC bets - make every single Xb1 game PC-compatible and bundle a PC version, which would widen their library (although it would cannibalize Scorpio somewhat). Or they could go on a spending spree and buy up every developer they can, and kill off the PS4's third-party support - Sony is no Nintendo, they can't survive on first-party games alone (even Nintendo might not do so much longer).