I think the key difference is that phone operating systems are designed around extremely aggressive memory management where any background process can be killed at any time. AFAIK macOS just isn't set up for that.
Upgrade to air if you do things like coding and video editing semi-regularly and upgrade to a Pro if you do long running intensive tasks.
Also conversely what about iPadOS where you can multi task on just 8GB too.
People have survived on 8GB Mac’s for a long time. I’m not sure things are as dire as you make them out to be.
Memory is the bottleneck with all Apple products. I have zero issues in terms of compute with the iPhone 12 Mini and could use it for years to come if the SoC were the bottleneck, but it can't even hold two apps in memory.
This would be a very competent computer if it came with 16 GB.