The point the GP was making is that if merging to main is frequent (bigger team) and build times are long (bigger projects), catching your branch up to master before merging can be hard, as master is moving ahead faster than you rebase+build.
Fully understood.. we also have a big team, a too slow CI, and much too many LOCs. The "merge lock" will ensure you catch up, you keep the lock as long as it takes (or until others get too annoyed and urge you to step back) - as long as you have it nothing comes between you and main at the point you claimed it.
