My guess is caching was added as bandaid for slow form processing and now that form processing improvements have shipped, those improvements are dwarfing caching.
I'd be open to removing that feature entirely and I'm looking forward to your findings after testing a few forms, @dcbriccetti. https://github.com/opendatakit/sample-forms or Share your BIGGEST or slowest form and win a badge! might be good places to start.