[Facetious Mode ON]
You're right. All us Apple-haters should lobby Apple to more than double the amount of RAM they put in their iPhones.
[Facetious Mode OFF]
Add at least $100 to the price of the phone, likely much more. Also increase the idle power-draw of the phone to keep the extra RAM modules fed. All to save maybe one second of wait time re-opening an app you haven't used in a while, and even then only if Apple makes significant changes to iOS to stop it aggressively saving RAM, which would massively screw over anyone with an older device.
It's not practical to multi-task on an iPhone, the screen, even on the Pro Max, is much too small.
Might I suggest that instead of buying an iPhone 13/14 Pro Max Ultra Whatever, if RAM is a concern, you would be better off buying a basic smartphone to do smartphone related things (iPhone SE, iPhone 13, or one of hundreds of Android alternatives) and use the money you save to buy an iPad or M1 MB Air to do the tasks that are far more suited to them.