Should NASA Send Astronauts On Voluntary One-Way Missions?

It will be centuries before any Mars colony could be truly self-sufficient. (To the degree necessary to survive the loss of humanity on Earth.) And for that entire time it is entirely a burden on the founding nations.

The simple fact is that such a project is not going to be supported for centuries. Hell, even decades is a stretch. People lost interest in Apollo almost immediately after Apollo 11. Missions were being cancelled. Funding cut. The whole post-Apollo wishlist was binned (except for a few like Skylab to use up the already built and paid for hardware.) Both the Soviets and the US completely abandoned the moon for decades, even for robotic missions.

IMO, if you want true long-term "self-sufficiency" you need a web of profitable activities in space. Starting with the industry's economic self-sufficiency on Earth to end the space funding monopsony. That economic "self-sufficiency" would result in a gradual expansion of human activity in space, until eventually Earth is just one piece of the web. At that point, a global disaster on Earth (or indeed anywhere in the system) would be similar to a regional natural disaster today. There are enough other unaffected countries to offer support, aid, rebuilding, etc, to ensure it doesn't result in a long term or permanent decline of the affected nation/region. A web of thousands of for-profit activities and settlements throughout the inner solar system, expanding slowly outwards, each economically self-sufficient (like any profitable business), and while individually not fully self-sufficient, the web collectively would be multiply redundant, able to lose whole chunks without collapsing.

Importantly, by being economically self-sufficient, it would continue to expand when the funding nations inevitably periodically lose interest in big specific goals, moon or Mars, etc, as everyone did with the moon after Apollo.

Similarly, by lowering the cost and increasing the scale of human activity in space, things like science bases on Mars will be no more difficult or expensive than science bases in Antarctica. A minor side-activity, not the sole purpose of HSF. (Imagine the cost of Antarctic bases if it was the primary activity of global shipping/air-travel. Ie, that there was no economically self-sufficient shipping or aircraft industry. Because that's where we are today in human spaceflight.)

Mars can't develop that way. It has no purpose except its own existence; no "exports" except science. And science is already "owned" by the funding agency, it doesn't provide an independent income stream.

Worse, Mars would inevitably be the entire focus for the entire US space program, and due to the cost, probably shared with international partners, so become the sole focus of the entire global space effort. For decades. Until we get bored enough to move on to the next thing. That means that any expansion of human activity, including on Mars, other than supporting the Mars base, would be delayed by decades.

And worse still, judging by all previous space programs (shuttle, space station, Constellation, even Apollo), 90% of the technology wishlist will be cancelled within a year or two, due to the hideous cost of the program. No ISRU, beyond using the atmosphere. No mining ice. No deep cores. No long-duration vehicles. No nuclear reactors. No "domes". No Phobos resupply base. No Mars cycler. Etc etc. Just the bare minimum to meet the stated goal of "humans on Mars". Think ISS on Mars. One base, one site, minimal activity beyond supporting itself and some token science, minimal crew (4 or 6) rotated every six to eight months (if we can improve propulsion.) And there's a huge probability the