That's a good question, without looking into any of the code id say bandwidth cost goes higher when moving away from server side rendering since you have to send the code for client side rending to each client which connects.

You say that, until you’re one of the unlucky people who discover that cloud DBs are just cloud VMs in disguise, and those cloud VMs have network throughput limits.

A fun part of a retro at my company last year was me explaining to a team, “had all of your pods’ requests succeeded, the DB would have been pushing out well over 200 Gbps, which is generally reserved for top-of-rack switches.” Of course, someone else then had to translate that into “4K Blu-Rays per second,” because web devs aren’t typically familiar with networking, racks, data centers…