I can't agree, I think it is two sides of the same issue. Everywhere in the bubble is the same, hence there is no temptation to move, as there is no change of surroundings achieved by moving. If you add to that the monetary incentive to stay, then you get what Braben was complaining about - players just moving around within their little sphere of systems.
I actually never did strongly agree with what Mr. Braben seemed to express regarding CMDRs not moving around. The idea of everyone being drifters is an interesting concept against the backdrop of the cut-throat galaxy, but in practice, perhaps seems to require that every CMDR be painted with the same brush?
First things first, I suppose that I must mention that I tend to play my CMDR within a sort of roleplay, and not everyone will do this. He's an independent. One who's been up to his ears in combat (and I have, in other games), and has turned is back on the violent lifestyle, and on the political scene. He'll make his way doing some trade (though not a preferred career), passenger runs, salvage, and mining. If getting ahead means violating his principles, he'll as often choose to stay behind.
So for this CMDR, not all systems are the same. There are systems out there which stink for mining and salvage. I'll never settle there. There are little gems though... pristine rings neighboring mining outposts, landable planets and moons, in non-superpower controlled space. I'll work from these systems for months or even years, supporting certain minor factions as I can. I learn every neighboring system and faction by name, their stations, outposts, and surface ports by name. It's great knowing the area like the back of my hand.
And thus I do fall into just moving around in my own little sphere of systems, for periods of time. But for me, this is a very enriched experience that enhances my CMDR's roleplay. Yet, when I've rarely shared my little "gem" locations with a friend or two, and they didn't really see anything special there. They have other interests, which are better served in other places. To each their own.
Still, it's not like I don't get around, even being a very "immobile" CMDR, I've traveled around 300,000LY total, now.