Console generations are won and lost within the first 2-3 years of their launch. I mean for the might that is the PlayStation brand, they never really recovered in the PS360 gen. The problem with all these what-if scenarios is that the only way they are relevant is if the competition is just sitting there and doing nothing.
The PS5, is currently at the most expensive price point it is ever going to be. Chances are, that by this time next year, or Xmas next year, there could very well be a $299 PS5 on the market. Its like people forget that you can already get a Series S for under $299 right now, say they get it down to $199, and get the Series X down o $299, those consoles will be competing with a $299 PS5. But think about this, who would you put your money on on being able to get the prices down faster?
The other problem and this is the bigger one, is with consoles, success breeds more success. What is the market gap going to be between the PS5 and the Xbox by the end of this year, what about next year? The more successful the PS5 becomes, the harder it becomes for the series consoles to do well. Saying the XS consoles will break past 60M this gen is to say we expect them to sell significantly better this gen than they did last gen.... why? What are doing dining now, or have they done, or has happened, that would make anyone believe that they are going to sustainably perform in a way that pushes those kinda numbers? Expecting it to do 80-90M is flat-out ridiculous.
To me, if I were Xbox or just a practical human, my measure of success this gen would be to sell at least as many xbox consoles as I did last gen(so around 50M) and have a GP sub base of around 45-50M too.