Disclosure: I operate multiple collators on KSM and DOT SysPara, of which 3 are INV collators.
I fail to understand the reasoning behind your wish to see the ‘change to a completely permissionless or at least a permissionless maximized approach to collators’? I am not against such approach if there is merit to it, so I am interested to hear the reasoning behind it.
As mentioned by Coinstudio in currently open discussion on Polkadot referendum 1395 (link posted by you above) reasoning behind current model can be found in approved RFC-0007: System Collator Selection of Polkadot Fellowship RFCs. Available resource is also a discussion on an Economic model for System Paracollators.
Side note: Astar parachain is maybe not the best example for your case of permissionless collators maximization approach - out of 46 collators 18 are Invulnerable and 28 are permissionless. This mounts to 39% of Invulnerables - so not that different from current 50% on Polkadot System Parachains.