Given Bloomberg already moved most of their infrastructure to TS projects and incremental compiles already, so performance might not even matter or change subst

Given Bloomberg already moved most of their infrastructure to TS projects and incremental compiles already, so performance might not even matter or change substantially if they moved to TS only builds so long as they preserved project boundaries. Under the hood the TS compiler in incremental multi-project builds still essentially builds the equivalent of minimal DTS information for projects, but it caches it in a build file that's more compiler-internal oriented than the externally shareable DTS. A developer with clean/fresh clones would still notice a big performance difference, but amortized over a number of builds it might not matter in general practice. In theory at least, as Bloomberg notes projects and incremental builds are still newish and don't yet always have the performance characteristics they should have in the wild. That said, the impression is that a lot driving projects/incremental compiles is monorepos in Microsoft (at the very least) that have moved to/are moving to monorepos that are entirely TS only builds with few/no DTS intermediaries. (That's just me reading between the lines, of course, I could be mistaken.) The drive behind projects/incremental compiles sounds like it is attempts at massive scales of TS files.