it would be much better if we just restored freedom of movement for everyone.
I agree with this. It just seems to me that the freedom of movement for 18-30 only is a very cynical attempt to seduce the people that we need to stay. Brexit was a colossal mess up, as many people predicted. We shouldn't be in a state where we're scared of having young people because they'll see things might well be better in other countries, but that's what Brexit + far too many years of Consetvative government have done. That's where we are. Somehow we need to turn things around and for that we need the bright and able young people to be here. If they really want to go and travel and work abroad then they will, this isn't East Germany, we're not going to force them to stay.
I agree it's not fair, and my heart wants to say "yes! Great thing!" But it's far from ideal for many, many reasons and I don't think we should make it easier to lose people we need.
Either we all have free movement again, or we don't, is my opinion.