I can't recall which it was but one of the timeseries databases was bragging on the fact that there are certain situations where scanning a block of data is as cheap as trying to add finer grained indexes to it, especially with ad hoc queries. They did a bunch of benchmarks that said block scanning with compression and parallelism was workable.

And while compression typically leads to write amplification (or very poor compression ratios), in a timeseries database, or a regular database architected in a timeseries-like fashion, modifying the old data is deeply frowned upon (and in fact I've heard people argue for quasi-timeseries behavior because modifying old records is so punishing, especially as the application scales), so as long as you can decide not to compress some pages - new pages - this is not a problem.