I don’t think faithfulness to the source material is actually the answer here.

A faithful Bioshock adaptation probably wouldn’t be as successful, for example.

So much of TLOU’s success hinges on how well it did with audiences that hadn’t played the game (and likely never will) and it’s most popular and critically acclaimed episode was almost a complete departure from the story that took place in the game.

The only real lesson to learn is to have very good writing that appeals to a wider audience than just gamers. Or to make games that take their storytelling cues from prestige TV.