Just because many do it, doesn’t make it OK.
As an end user, I really dislike the garbage that plugins leave behind. Imagine the same behaviour on your Android/iOS device with apps occupying storage even after they were completely removed.
A solution would be to export the database (MySQL dump) and store that information in a “.php” file in the “wp-content/upload” folder as a data store.
If/when the plugin is re-installed, use that dump file to re-populate tables.
