I would say between 55 to 65.

And yes, at the beginning of this gen MS was my most hated company out of the three. Now it is my favorite.

I will say 80-89 mil between the two.

The budget console of 299 usd is a great entry point into next gen, and overtime we may see people upgrading to the X as the generation goes on (essentially double dipping). MS is gaining a lot of positive press with their BC stances, gamepass, and generally pro consumer practices. I can see them reclaiming the US and UK with ease, especially if they keep their Bethesda IPs as brand exclusive.

However around 80 mil will be the ceiling here, as PS will still be ahead in Eu and Japan. Some people with capable PCs will also opt to play XBox games there as well, which will prevent console sales from going much further above that. On the flip side however, many consumers still prefer the convenience of consoles. This will cause many who would primarily only game on PS5 to at least get a series S if they have any interest in MS newly aquired IPs and studios, further adding to the total sales of the series S/X.

More than the Xbox One but not massively so.
I voted 50-60 million, but somewhere between 60-70 wouldn't surprise me either if they play their cards right.

Or 69

More likely Tom Brady has another 5TD game, than Jets winning 5 games.

I'm in the upper 60 mil camp.

MS has always been able to keep my business,
I'm also a shareholder, and use their products in various assets of my line of business.

If talking about the upcoming console, I've owned every console (Nintendo/Sega/Sony/MS/3DO/etc) since the 80's, so don't see that changing.

Microsoft is much better positioned at the start of the 9th gen than the 8th. However, what's good for the XB brand (Gamepass) may not be great for XB console sales. Nevertheless, I expect that having both the most powerful and the most affordable next gen systems will help. Then there's the expected shorter length of this generation holding numbers down. There's the Bethesda ideal that will likely help the brand a lot in the long term, but probably won't do much of anything over the first few years of the generation.

With all of that in mind, I'm guessing 67 million units sold during the 9th gen.

Overall though, I expect MS to become the market leader in gaming sometime around the end of this gen to maybe 2030. They have such a massive headstart on Google and Amazon, and they have such massively deeper pockets than Sony and Nintendo that I see them as the most likely to come out on top as the distribution model(s) shift. Plus, they're still in the traditional gaming space, and likely improving their position there as well.

I really don't know how this is going to turn out.  It's unclear to me if their focus on Gamepass will help or hurt XBox hardware sales.  I voted "less than 30m" mostly because I'm guessing it will hurt hardware sales.  Gamepass subs will probably be a lot more than 30m once the generation comes to an end, but that doesn't mean that Gamepass members have to play on a XBox console.

I'll go 60 million.

55 million, which should bring it about 5 million above the Xbox One's lifetime sales. It's a tough spot for Xbox hardware when competing with PlayStation, Nintendo, and PC gaming.