Microsoft has promised a rich lineup of first-party games for the Xbox Series X, many of which will be unveiled at the Xbox 20/20 event this week on July 23.

In an interview with Polygon, Xbox boss Phil Spencer said that the Xbox Series X will feature "the most diverse collection of first-party games." And Spencer said that these games will be available not only on Xbox Series X, but also on Xbox One and Windows 10 PCs, as Microsoft "grows the Xbox ecosystem."

"I honestly think we're in the best launch lineup position we've ever been in on Xbox," Spencer said. 'I think that's a real strength, not only in terms of backwards compatibility, but in terms of the strength and depth of games that are available on the Xbox Series X from day one, and the fact that Game Pass is enabling us to lower the total cost of ownership of the console.'

Spencer touted the fact that "Halo Infinite" will be the launch title for the Xbox Series X. This is the first time since the original Xbox was launched in 2001 that a "Halo" game will be available at the start of a new generation of consoles. According to Spencer, however, the real difference between the Xbox and the PS5 is the approach taken to making the game playable on multiple platforms.

"I think the fundamental difference is that we're trying to grow the Xbox ecosystem," Spencer explained. 'We're trying to build it around the player and give them choices. If they choose to play on a console TV, we want to give them the absolute best console experience. And I think we have that."

However, Spencer noted, not everyone will be able to afford a new console at launch, especially given the financial problems caused by the coronavirus pandemic. Therefore, not only can they enjoy the games on their current Xbox One console, but thanks to Smart Delivery, they can also get free Xbox Series X versions of games they own on their Xbox One if they decide to upgrade to the next-generation console.

"I don't think anyone should have to buy a new game collection when they buy a new console," Spencer said. 'I fundamentally don't believe that. I think great games should be available on new consoles. But you shouldn't have to buy every new game to play on that console."

Sony seems to be taking a different approach with the PS5, seemingly focused on creating a next-generation gaming console designed to run a new wave of visually impressive games. Spencer said that "multiple strategies could be successful," but Microsoft's approach to building the Xbox ecosystem appears to be quite different from Sony's console strategy.

We have already mentioned that Microsoft's Xbox ecosystem will be formed by both generations of Xbox consoles, Windows 10 PCs, and game streaming via Project xCloud bundled with Xbox Game Pass. For these reasons, an immediate upgrade to the Xbox Series X does not appear to be mandatory for Xbox fans.

Which strategy will come out on top remains to be seen. However, much of the success of a new console depends on the games it brings to the table.

PS5 games are already quite extensive, but Xbox Series X games, as far as has been revealed so far, are mostly third-party titles. On Thursday, a large number of Xbox games will be announced, possibly including "Fable 4."