[Eridrus]

I don't really know what sorts of scale you've worked on, but software operating costs growing roughly linearly is pretty normal.

You need to process X% more requests, you need X% more machines.

You need to store X% more data, you need to buy that much more disk, etc.

Many things scale worse than linearly too.

If your SaaS product doesn't do very much, sure, the costs might be cheap, but plenty of SaaS products just do a lot, processing lots of data for customers.

Datadog it a canonical example of an excellent software business, but even still, they have real infra costs because there's just a lot of data to process.