I suspect that FDev has a specific reason for not doing that, though. And I suspect it’s the same reason you can’t colonize from colonia and other places. I think it has to do with power play.
Like other things, the antithesis of allowing people to buy their way for (easily earned) credits when there is a game to be played. It will just benefit those with more credits.
Even with those proposed figures, there are people who can buy a system on the far side of The Abyss on day 1. Sure, they'd need to spend the next <4 weeks doing ~45 hours of carrier jumps and tritium transfers to get the founding materials there, with maybe 6 or 7 supporting carriers loaded with tritium to make the trip (abandoning/decommissioning as they empty along the way,) but it wouldn't be impossible.
There is a lot of history in Colonia from player led factions and use of BGS. Who knows, maybe the area will manifest a power of its own one day, but it is probably for the best it remains more anarchic.
Take a look at what has been done in a few months to support Distant Worlds III in Orion; It just needs a committed and well-organised team. There are already many colonised systems some 1500LY out from Sol towards SagA/Colonia. Even assuming stopping to build out some supporting infrastructure every 500LY, it isn't going to take decades.