[1] https://www.jetbrains.com/store/?section=students&billing=ye...
It's like how after using Apple hardware for years I couldn't put up with most Windows laptops -- either they were HiDPI ultrabooks with no performance or they were sloppy gamer machines with no class.
Learning JetBrains gets you hooked.
In my experience most SaaS apps do not filter this out and allow re-sign ups with sub-addresses.
Gmail has an additional behavior that dot character is ignored in local component of the address . multiple@gmail.com, mult.iple@gmail.com mult.ip.le@gmail.com all route to the same inbox as well.
[1] https://datatracker.ietf.org/doc/html/rfc5233 [2] Less common in work hosted ESPs but almost universally default enabled in public ESPs for consumers.
Two or three mails have been misplaced in a decade.
It would be feasible to change something like that without breaking security now.
Google can hardly start allowing/routing a new account for first.last@gmail.com when you were getting it for years even though your account is firstlast@gmail.com and sensitive communication like say from your bank would routed there.