Avoid loosing input data is far to complicated

Hi
To create a webform where you help the users not loosing their inputs is complicated (or almost impossible for the average web-developer)
See my post here:
https://stackoverflow.com/questions/73680307/beforeunload-does-notwork-on-ios-even-though-the-documentation-says-it-shoul

Has the web turned into somthing so complicated that only Google and Microsoft has the resources to run sites (like gmail) where users dont loose data ?

Please comment… Thanks in advance