I was going to say something like this but you beat me to it. Moving more application state and logic to frontend SPAs reduced the need for so much backend work.
Backends are faster and more robust when they don't need to manage the "session" so much and instead just validate the final API request data and if they queue up anything it's those actions that require database transactions or to publish a message.
Backends are faster and more robust when they don't need to manage the "session" so much and instead just validate the final API request data and if they queue up anything it's those actions that require database transactions or to publish a message.