Also: scaling isn't just speed, it's also capacity, HA, failover. Are you running 100x4T NVME in a single server?

Edit: fun little story. Some time back, I wrote a compaction strategy for Cassandra designed for time-series data. That strategy (known as TWCS) is now widely deployed, but for the first year or so, it was an uphill battle to get it accepted into the project over the existing options (high barrier to entry for fairly obvious reasons). I had given a talk at a conference and made the code available online - my employer was going to use it, so giving it out was a good way to help iron out any wrinkles, and maybe some early adopters could help me get it into the project.

There was a Fortune 500 company who sent me one of their products - unsolicited - as a thank-you, because they had deployed my compaction strategy, and it apparently helped them a lot. I asked how much, and their answer was something like "About $20k/month". In my mind, I thought that was great - probably let them decommission somewhere in the range of 5-20 servers, which sounded pretty good to me. Then they said "per cluster, and there's 10 clusters so far".

Now, the $200k/month savings is cool and all, but the real point is think about how many machines are involved here to be able to SAVE $200k/month just by changing the way data files are combined.