Wait a sec, I thought the monorepo was the SV canon. As in, "we have to keep our velocity high, to deliver customer value multiple times a day, so everyone should be able to make changes across the whole stack in a single commit, and release to production in five minutes."

In my opinion it boils down to a single factor: if you don't have proper APIs between your components, then you will need to make cross-cutting changes across the whole codebase on a daily basis, thus you need everything in the same repo to work effectively. If you don't have the time to work out the proper boundaries/APIs between your components, then sure, by all means go for the monorepo! But that's like not fixing a blown tire just because you would need to stop to do it.