The OP isn't wrong, as such, but is referring to a very narrow frame of reference; the frontier he exists in disappeared for me the moment my jump range got above about 80 light years; on the way back from exploring, in a single jump I'd go from no stations to heavily populated systems, straight through any frontier there might be. That can be a good thing or a bad depending on your needs and perspectives, and OP isn't wrong to deplore the loss of his prior way of life...
... it's also not provable yet if it's a good thing or a bad thing; just becomes humans adopt this or that en-masse isn't itself an argument for whether something is long term good. I'd name examples, scientifically proven to be problematic at scale, but there will always be contrarians and stick-in-the-muds that will argue against basic science to claim that no, everythings perfect or I just don't want to change... and by that I don't necessarily mean OP again; Luddites weren't technically wrong that industrialisation was coming with a huge human cost, as well as benefits.
But keeping it Elite focused; I'm not sure that colonisation in game will be good long term. Sure it'll boost FDev's finances short term, from selling Arx for station renames and skins, but I'm not sure it's been thought out well. Having worked in the industry, I'm not sure there's enough staff available to even dedicate to thinking wider game design out philosophically, but specifically here, launching it with the economic design of system building incomplete, beta quality, and hidden from the players, as well as hideously bugged was bad enough, but it had to be obvious from decades of player behavior in sandbox games exactly what would happen; people would immediately go for the high reputation locations, grab as much for their factions as they could, and just generally turn the galaxy into a predictable mass of attention in some spots, and throw away systems everywhere else.
Counter-intuitive to OPs argument, this actually guarantees "frontier" systems almost everywhere, because they'll all mostly be stepping stones to getting somewhere else, or just going for the most efficient method for maximum capture. You don't design a game around soul-sucking grind and expect to get artists, rather you get obssessives with plenty of free time, and min/maxed identikit colonisation strategies. My own preference, to encourage deeper system building rather than wider, would actually be more destructive to OPs preferences, because if he was living near my player faction, suddenly he'd have huge cownstruction projects designed to roleplay what I want on his doorstep...
It's entirely reasonable, perhaps even essential that people like OP get to ask questions about whether the cost of that kind of colonisation was worth it. I just don't think he'd like much any attempt to change colonisation though, except to restrict it entirely.