> The sheer amount of observability data you can collect in wide events grows incredibly fast and most of it ends up never being read.

That just means you have to be smart about retention. You don't need permanent logs of every request that hits your application. (And, even if you do for some reason, archiving logs older than X days to colder, cheaper storage still probably makes sense.)

> That just means you have to be smart about retention.

It's not a problem of retention. It's a problem caused by the sheer volume of data. Telemetry data must be stored for over N days in order to be useful, and if you decide to track telemetry data of all tyoes involved in "wide events" throughout this period then you need to make room to persist it. If you're bundling efficient telemetry types like metrics with data intensive telemetry like logs in events them the data you need to store quickly adds up.