eli5: How do games that have existed for years (example: skyrim anniversary) receive massive download content that adds quests, items, maps not crash?

Question

How in the world do games that are that old run with new content without getting too glitchy? Is this trial and error that developers work on? Are certain games unique that slapping on content is as easy as a puzzle?

In: 4

Answer 1

Clarification: why do you think they should? They use the same tools to make the DLC as they did for the original game. It’s 100% compatible.

Plus Bethesda games are _always_ glitchy.