All of that disagreement basically stems from different ways of looking at space exploration.
You can look at space exploration from the perspective of 'doing more stuff like we're doing now'. Don't do $25B/year worth of science in space, but $250B/year. Surely, that will be ten times as good! Instead of sending a dozen people to near-earth space and/or the moon, build a 100-person tiny habitat to act as a moon base.
Like earlier in the thread, I'm very skeptical and critical of this kind of thinking as it's ultimately quite pointless. There is nothing in space that we don't already have - and have much better - on earth. All elements we need for earthbound ventures are right here on our planet, and there's probably already extensive supply chains for them. The type of things we might want to do in space or on other planets can be done just fine without humans physically being there. So there is no real need to... do anything to establish more than a PR stunt on the surface of Mars.
So rather, I view space exploration as a true establishment of our society outside of earth. Not a temporary outpost or scientific research station, but at least a best effort towards establishing a complete local economy with everything that has to entail. This doesn't mean we have to plop down a fully formed society at once, of course this will be a gradual build-up with - initially - a lot of leaning on Earth resources and flying in resources that are initially scarce on Mars. But there's a fundamental difference in setting yourself up for a temp base or PR project versus setting yourself up to try to properly colonize a planet. In the first instance, you can work from a template and stop development on particular technologies (like launch cost reducing methods) at some point. Because it will be enough, and doing more is just a waste of money.
If your goal is to not just set up a single base but continuously interact with a separate but connected economy outside of earth, there are incentives to continuously improve upon things like launch methods. There are incentives to invest big in the long-term future, rather than just iterate on current technology. Suddenly, an investment of 20 or 30 billion into a skyhook or moon-based mass driver becomes much more palatable to governments and peoples. These are somewhat large amounts of money, but still tiny investments for large economies or earth's economy as a whole to make, and fundamentally change the pace and scale of space exploration.
Because indeed, if all you're doing is using chemical rockets to get stuff into space, it's going to be hundreds of years before we have anything beyond an ISS-sized base on Mars. Within our lifetimes, maybe we can set up a single manned mission and the chances of that being one-way are pretty big. It's neat and it's certainly going to be a monument of our society, but it's not the start of something more. It's more like the end point.
If we decide to expand our economy beyond Earth, suddenly we can have cheap spaceflight in our lifetimes, and actual cities on Mars as well. Contrary to popular belief, it's not actually fundamentally that hard to do stuff in space, we're just doing it in extremely wasteful ways as those are easy to do without establishing space-based infrastructure first. But just for some perspective: it only takes 60MJ or about 2kWh per kg of mass to get to Mars. Wholesale, that's a few bucks worth of energy per person. To get an entire car with one person into space - a massively inefficient way of going about things - takes a few dozen dollars worth of energy. But right now, we're not even that 'efficient' - we're spending about a thousand times as much energy as we should need to get stuff into space, because we're using propellant and the rocket equation is a bitch.
You don't need any new or advanced technology to fix this. Just put a (series of) skyhook(s) in space. Sure, we have to use rockets to get the hook there and that's going to be a LOT of rockets, but once it's there, suddenly spaceflight is 1/100th the cost. Or if you're not a fan of skyhooks, consider high-altitude mass drivers.
And to expand this further - the same applies to Mars itself. Infrastructure has this magical way of paying for itself many times over if you plan ahead. I'm especially progressive on this point as I'm in the camp of prioritizing infrastructure before a real economy has really been fully established. Basically the first thing I'd consider doing on Mars would be to build a mass driver in situ, both for launching into orbit and traveling around the planet.
