Traffic within a data center is relatively cheap, is it not? Of course, I think managed network proxies tend to be expensive, but I think that mostly comes from the machine costs, not the network itself. You pay a bit of a tax for network serialization, but it's unlikely to be the bottleneck in most things ime.

Plus, applications built on an external database (e.g., postgres not sqlite) will already have 1 hop. Going from 1 to 2 hops is less dramatic than going from no hops to 1. And I guess implicitly any service sending lots of data to the client already has 1 hop.

Imo the only case where a network proxy would be egregious is an in memory database kind of workload where the response size is small relative to the size of the data accessed (maybe something like a custom analytics engine), but that's pretty niche.