There's a lot going on around Infinite and Halo/343 as a whole that makes titles and articles like these really difficult to understand and have an honest discussion around. Even though not many people play on Steam, there are other ways to play it on PC and Infinite is still the 6th-most played game on Gamepass, with it still being relatively popular on its main platform - Xbox. At the same time, though, there are some long-standing and glaring issues with 343's Halo, and it's not terribly surprising that Infinite didn't end up capturing and retaining the playerbase it maybe ought to have.

On one side, people in the gaming community (and the Halo community) eat up articles that go "XYZ game is DEAD because-" as it allows some pretty easy grandstanding and attention (or over on reddit/twitter, imaginary internet points farming). For the most part, Infinite is in a pretty okay state in terms of content (after 1.5 years) and player levels, and an article like this one is easy rage-bait for people to interact with.

On the other side, it's not terribly surprising that this happened. Before Infinite, I would argue that all of 343's games were resounding flops - not monetarily, they all sold well, but in terms of quickly diminishing playercounts, negative reactions from the community, meager launch content, or even flat-out not working (looking at the initial launch of MCC), 343 had yet to hit a homerun with Halo. The first few weeks of Infinite were great, but the cracks started to show quickly. Bugfixes were non-existent - such as when the BTB playlist broke in December and it took 2 months for 343 to fix it. Content delivery was also non-existent, the game shipping with very few modes and maps with the supposed 3-month seasons being delayed into being 6 to 9 months long, with the bulk of updates being for cosmetic content or modes that had been there on launch-day for other Halo titles. The challenge and cosmetic systems were explicitly frustrating and designed to be so, under the pretense of making people grind/play more, but which ended up having the exact opposite effect and drove players away. Shop and cosmetic prices were ludicrous, and there was no consistent stat or rank-tracking systems. No Forge. No custom games browser. Theater doesn't work. Etc. Etc. Etc. Etc.

Even though Infinite is in a decent spot now and I find it fun to play, it's not surprising at all that the playerbase is at levels lower than it should be. No, Infinite or Halo aren't "dead," but 343 has done a good job at whittling down a titan of a franchise into a middling AA-level game that only the most die-hard fans care much about.