Almost all games have an inherently limited lifespan. How many games released 20 years ago are still selling well today? Games aren't like other software where you can keep enhancing the product and keep getting new sales. Thus games developers have to focus more on maximizing short term revenue rather than building a sustainable business around particular products.
There are a handful of counterexamples like Madden NFL but only very few.
In most cases, a re-released game is an entirely new game SKU using the same IP, just as a movie remake is a new movie based on a previous one. And similarly, once released, most rereleased or remastered games have a short tail.
In 2000, a 10 year old game was positively prehistoric, some unrecognizable thing only distantly related to the current forms.
In 2010, a 10 year old game was quite old, but a recognizable ancestor of new releases.
In 2020, a 10 year old game was kind of old. You could tell the difference if you had high end hardware and were tuned into certain details, but the new games were essentially the same kind of stuff as the 10 year old games.
The pace of advancement is slowing and game design has reached a mature plateau; games having greater potential to last longer each year. If a game can last more than a few months then there is a reasonably good chance it can survive for several years at least (presuming the publisher doesn't decide to cut it off to sell a new version, which is a popular tactic.)
Maybe not 20, but still long time CS2(CS:GO really like Windows 11) launch 2012, DOTA 2 2013, LoL 2009, World of Tanks 2010. And more. All still making money and surviving...
