They have one or two members that provide substantial financial support for projects such as this, by that I mean well into 6 figures. It's their choice. Tythe or no tithe.
That's not what Brian Thompson said in his MR interview: https://www.manxradio.com/news/isle-of-man-news/steam-packet-md-hugely-disappointed-by-industrial-action/
Of course there's no guarantees but I wouldn't be surprised if IOMSPCo have a rolling operating and capital budgets drawn up for 5 years hence, based on current market conditions and is reviewed at least monthly. If I were the Chairman and/or CEO that's what I would expect to see.
In my experience you won't get any oil if it's not paid for in advance, either by bank transfer or debit/credit card. I doubt there are many, if any, who have credit terms directly with the oil suppliers (of which there are two, as far as I know).
We can all relax, Bill's got it sorted:
https://www.manxradio.com/news/isle-of-man-news/completing-gas-bill-in-one-day-signifies-the-urgency-of-the-situation/
The only other option is for new builds to have electric heaters built-in which will then put pressure on MUA to meet the increased demand. Wind turbines are not going to be able to take up that increase.
I can see that new builds will be erected without any heating provision at all, not even heat pumps. Installing heating will be an optional extra and at a very significant cost.
Of course I knew that Stu was only joshing but as you say, it's the lamest of excuses for doing fig all about giving their customers the best service possible.