For the performance boost it could offer the unsavy user stuck on a HDD, it was probably worth it to many. Gross to be the middleman, but it is what it is.
Another computer shop i worked in charged $90 for virus removal, but we also eventually made it policy to just reformat/reimage the drive and remove all the crap and fully update the OS. Prior to that the policy was "remove viruses, remove crapware, update OS", but we had a few customers that had machines with 30,000 viruses. I forget what the record was, but it was way up there in count. Trying to clean those machines had a marginal failure rate, enough that it was costing the owner money to have us repeatedly clean them without payment.
No one wants to tell a customer that they need to find better adult content sites, and that we won't be cleaning their machines without payment anymore!
"just reformat/reimage the drive and remove all the crap"
And that is not more work?
It was usually the way I did it, too. But this requires checking with the owner what apps are important, saved preferences, where are the important files stored (they never know) etc.
No one wants to tell a customer that they need to find better adult content sites, and that we won't be cleaning their machines without payment anymore!