I can point to dozens of single-player only games which are always online, and KSP2 doesn't even have that argument anymore, allegedly. Games are no longer individual experiences, they are "services" now.
Plenty of games with mod support have DRM.
I could easily counter saying that the only reason to believe it will stay on steam is hope and optimism. Despite what advertisements for lawyers tell you, past results are a good indicator of the future, its sort of what the scientific method is founded on.
Easy. Extra skins, extra parts, extra planets. You know all those upgrades for the buildings in career mode? Easy micro-transaction targets. Want to revert to launch for the 11th time that day? Sorry, you've run out of revert tokens, wait 24 hours, or pay the low, low price of 500 kurbles (i couldn't think of a better pun for a currency then with "ruble", sue me). Why would they do any of this? Because it would make them money, and people would pay for it. The people who make these kind of decisions don't care about you, they don't care about the game, and they certainly don't care about how you see them, because they know you're still going to buy it (Not "you", specifically, I don't mean this to be a personal attack).
It would cost extra money to hire or train support staff, and there's not enough revenue to be gained to offset it, so there's no reason to support it. They'd have more of an incentive to try and get it to run on iOS or Android before supporting MacOS or Desktop Linux.
As I stated, the team appears to be quite respectful of the original, and from the developer story trailer, I have no concerns on their judgement or ability to deliver. But the point you seemed to gloss over is this: They don't matter in this discussion. They don't get to make those decisions. They get a mandate from corporate, and they comply, or they get to spend some time polishing their resume, and given the job market in the industry right now, I think the choice is obvious. Until we have direct, explicit confirmation otherwise, and not through some wishy-washy "community manager" replies on a forum (I get you're just try doing your job with the information you have), I see no reason to assume anything but the worst.
I can appreciate your optimism, but optimism and leeway is how we got into this situation in the first place. There's a great piece of advice when looking at trailers, ask yourself "what aren't they showing you?", because that's what they don't want you to see. Then ask yourself, "Why don't they want me to see this?".
