why we disable the classic project option?

[Nivrutti Shinde]

why we disable the classic project option? when sub task is not enabled for this. We can not give admin access to each user. It is very frustrating

[Nic Brough -Adaptavist-]

The classic projects have shared configuration that would allow someone who can administrate them completely trash everyone else's projects.  So the creation and configuration of them has to be done by admins (who, in theory, know how not to trash other people's projects).

Next-gen projects do not support sub-tasks.  Yet.

Most Jira places have a small team of admins who accept that one of their tasks is creating standard projects when they are needed.