I think ultimately it stems from lack of source code ownership / use of open platforms / clearly defined interfaces. Best case, with clearly documented and def

I think ultimately it stems from lack of source code ownership / use of open platforms / clearly defined interfaces. Best case, with clearly documented and defined interfaces, you can rewrite or swap out an entire component. Worst case, you have no source, no standard technologies, and no interface barriers, in which case your choices are leave as-is (no additional features) or replace everything (impractical due to size of codebase / legacy functionality coverage).