Developers use what is available off the shelf. If there is no easy and straightforward way to send data with a client code over the wire, they will send “function onload() { unjson(await xhr(endpoint, tojson(data))) }”. Blame should go to stupid runtimes, not developers.
You were motivated by submitting a cool demo, they are motivated by not being fired after deadlines. An additional network hop is nothing compared to not shipping.