It's potentially the opposite. If you instrument a codebase with documentation and configuration for AI agents to work well in it, then in a year, that agent will be able to do that same work just as well (or better with model progress) at adding new features.
This assumes your adding documentation, tests, instructions, and other scaffolding along the way, of course.
This assumes your adding documentation, tests, instructions, and other scaffolding along the way, of course.