These are all fixed costs not per-unit costs. If you sell 10,000 ebooks or 10 million ebooks, the costs are basically the same.

And book themselves are 500k-5MB in size typically, which is a single HTTP request, basically. Actual costs of storage and distribution are basically zero (per unit). And sure 10M books is more traffic than 10k books but we're talking $0.10/GB or less in baseline traffic. This is like Cloudfare free tier levels of traffic. And while the traffic costs do scale, it's completely dwarfed by the amortization of fixed costs like editing, formatting and cover design.

As for tech support, it's not the same. Publishers have to handle returns from retailers. Ebooks don't. It's no more complicated than revoking a key and the actual process of requesting a refund requires no human intervention either.

This really feels like I made some blanket statement than offended your sensibilities so you decided to argue without knowing why, if I'm being honest.