I actually worked with clearmake and bunch of other rational tooling in one of my early gigs and don’t remember much in a way of cache improvements. Soon as you’re doing some non-sandboxes io which make-based tools totally allow it’s out the window anyway
Curious how clearcase works I found https://www.ibm.com/docs/en/rational-clearcase/7.1.2?topic=s.... They appear to be hijacking the open() and write() syscalls, so in some way they actually do have a sandbox that provides more accurate knowledge about the build graph than what the makefiles tell! Otherwise yes, makefiles themselves are very unsafe and frequently have errors such as underspecified dependencies or implicitly produced outputs, with no guardrails that can prevent them.
Wether or not that sandbox blocks incorrectly declared dependencies is unclear. Last time I used clearcase many eons ago it surely did not. Our project had tons of classic makefiles issues like not depending on included headers. Remote builds were also magnitudes slower than local builds, our network was maybe not the best, also reading the page above how the “shopping” algorithm works you can imagine it being fairly slow anyway. Maybe that was best, imagining how incorrect dependencies mixed with remote caching would result gives me nightmares.