When you use a good build system like Bazel modules do not save 10 minutes a day. The time saving is negligible. That's why large C++ shops do not care about modules and only volunteers are working on them.
Not everyone uses bazel. I would wager that a vanishingly small amount of people use bazel. If people using other things was enough to not let things be standardized we wouldn't have asio, ranges, fmt. Precompiled headers also exist, so why would we standardise modules?
I have no idea how many people are slopping C++ code. So lets just calculate it per 1000. Assume modules save an average of 10 minutes a day.
1000 X 250 days/year X 0.167 hours/day -> 41,666 hours a year per thousand coders. Or 21 man years.
Yeah you'd think it'd be worth funding heavily.