The only way to make that simple is to centralize the version control system so that you can have a single arbiter of who has what locked. To add easy locking to Git, you'd have to turn it back into a non-distributed VCS.

I don't think I need to sell the value of DVCS over VCS, but what seems to get lost is that buys you a certain amount of essential complexity, expressed in the CAP theorem and its consequences.

We discussed this deeply on the Fossil forum: https://www.fossil-scm.org/forum/forumpost/2afc32b1ab

We came to no easy answers, because there aren't any. You only get a choice of which problems to accept.