National Pride and bureaucratic inertia are two factors which can keep some big project going well past it's Sell By date.
Except of course that British Airways was a private operation for more than 2/3rds of the life of the Concorde, and they flew it at a profit.
Why did Boeing cancel it's 2027 project? Why have there been no other SSTs (either European or American) since then?
Because they aren't economical.
More because people who are worried that they might not be economical and the companies behind this sort of development are risk averse (when they aren't on a government contract, anyway).
Anyway, why are we even discussing the blasted Concord? Can we just stop. It's a real thing, it operated for nearly three decades. You think it somehow proves something, I don't agree. We won't see eye to eye but who cares because the remaining Concordes are museum pieces now. I'd rather discuss the topic at hand.
This is the Handwavium:
you can just dig under the dirt a little and hit a layer of pure water ice
But what you wrote was:
This is the crux of the disagreement between us. You say it's hard but doable, whereas I think you're Mars mission relies on Handwavium to convert chemical transformation formulas into actual non-laboratory processes.
How is the availability of water on Mars therefore the handwavium? That's not what you meant when you wrote that and you know it. I'm going to have to assume that your information about extant efficient electrolysis systems was very out of date, but you finally looked it up and now you're trying to claim you were talking about water in that last sentence. It doesn't even make any sense for water to be what you were talking about.
A few shovel digs and up comes potable water?
You can't just keep misrepresenting what I'm saying. I didn't say shovel digs, although there are certainly places where you could reach the ice with a shovel, or maybe just a broom to sweep off some of the soil. The use of powered equipment would only make sense, even if only to haul it. I'm also not saying that you could just do it anywhere. Clearly you have to choose your location so that you have access to a usable source of water if you want it to be this easy. I'm also not saying "up comes potable water" which implies that the water will be liquid and have nothing dissolved in it.
What I'm saying is that we've already found spots, within range of areas that are suitable for a base, that have, at the very least, millions of kilograms of concentrated water ice. We've been able to identify these spots specifically because the ground over the ice in these spots is thin. That means it can be dug up, cut it into blocks, thrown into the back of a truck and driven back to the base. Then it can be melted, purified as needed (using the consumable supplies I mentioned way, way back) and used to make oxygen, as raw material for fuel-making or concrete or other chemical processes or just used for drinking, re-hydrating food, growing food, brushing teeth, etc.
There just isn't that much mystery about how you would do it. We're still not as sure about all the ideal sites for it, but we know some already (and remember, this is only if you want to do it the really easy way, there's water in plenty of other places too, it's just not in the form of almost pure ice. The exact equipment and techniques you would use are still up for debate and experiment as well. Traditional ice cutting techniques probably wouldn't be up to snuff because the ice could be so cold it's as hard as rock or even steel. On the other hand, you can melt a cut through the ice pretty trivially with some sort of hot wire or heated blade. Or it might be more efficient to just blow it into fragments with explosives. Heck, for a Mars mission, a laser cutter might not actually be far fetched. Or maybe it would turn out to be more efficient to melt it at the source and pump it into barrels.
In reality, it'll be akin to strip mining.
If it's decided that it's better to locate a base too far from any rich source, then it might very well be like strip mining. Or it might be like repeatedly boring new wells, heating them and pumping out the water. Or there might be some better technique (I've seen some interesting ideas for microwave devices for liberating water from the soil).
The point is, once you're there with the right equipment, it's entirely doable. The debate about water on Mars is pretty much settled at this point. It's there, it's not just theory any more (well, it is technically still theory in the same way that everything is still theory). Anyone still insisting that the obvious water features on Mars are actually Aeolian or caused by CO2 or some other exotic process doesn't have much of a leg to stand on. If it's there, we can collect it and use it.
It's still hard work, and the water will need to be carefully used. Astronauts would need to bathe with small amounts of continuously recycled water and use extremely low or no flush toilets. They wouldn't be able to get away with using the 400 or so liters per day that the average American uses. The critical point is that it is _not_ impossible.