As fas as I have seen, 99% of in-house solutions are tailored for exactly 1 use case - the company that built it. Existing solutions like InfluxDB are made way more generic.

Companies like Twitter, Uber etc can spend many millions and won't notice so they can build tailored databases for themselves.

Will someone else use it? Probably not (sure unless this is something new or that differs a lot from existing solutions and gives a lot of benefits)