I see Mars as a gateway because it serves as an easily sustainable base and has plenty of resources to support other space endevours. Plentifull insitu resources reduces the cost of a permanent presence in space making cancellation much less likely. Mars also has plenty of resources to serve as a launching pad further into the solar system. There are pluses and minuses for both the Moon and Mars in a contest between the two, but as a chemical engineer I see Mars as a far better platform for self sustaining industry than the Moon. I have not done detailed analysis on this just the old engineering judgement approach of numbers of resources, outlines of proposed recovery methods, and relative resource abundance.

LEO is definitely a staging gateway near term, but it has no raw material other than energy. It will always rely on supply from somewhere else. It can never be a self sustaining permanent presence in space.

I strongly disagree with your generations comments about Mars. Tremendous strides in industry were made on Earth over a much shorter period of time with far less know how and no computers. You have the same basic problems to overcome for LEO: low pressure, low gravity (to a much lower extent on Mars), radiation (worse short term on Mars, better long term), lack of access to many resources initially (worse in LEO). The ease of reaching LEO is balanced by the lack of leverage and possibilities once you get there. This is similarly true of the Moon and NEOs, but even more so as the difficulty reaching them is similar if not greater than for Mars.

Regards,
Mark