Mars colonization will take off extremely rapidly, most likely.
Making propellant on Mars is easy, all you need is Hydrogen and power and you can make 16x as much mass in propellant as the Hydrogen you bring along. And this is with mere kilograms of equipment to process the martian atmosphere. Make no mistake, this is a big deal in a lot of different ways.
So that bootstraps you into being able to effectively explore Mars at all, because now you don't have to ship out all the propellant for the return trip, which is an exponential savings.
Now add to that the fact that Mars has a day similar to Earth and substantial quantities of subsurface ice (and small amounts of water in the surface soil). That means you can use fairly modest capital equipment (stuff you can transport using the same vehicles you send people, and capable of being powered fairly easily) to start mining water ice within the first handful of trips to the planet. Which means that you can have local supplies of: potable water, propellant, fuel for equipment that runs on internal combustion engines, breathable oxygen, and carbon monoxide (which I'll explain the significance of later).
With oxygen, abundant CO2, water, and inflatable structures you can start growing plants on Mars due to the light levels and day lengths. A colony could start supplying some of its own food within less than a decade.
But wait, there's more. Given the low Martian gravity it would be almost trivially easy to create an SSTO RLV that could travel back and forth between the martian surface and orbit, refueling on the surface with locally produced propellant. You could build these on Earth and send them over without crews and just enough propellant to make a powered, parachute assisted landing before being put into service. They could visit a station in Mars orbit which would make it easier to make trips back and forth to Earth.
Additionally, by using a cycler (a spacecraft which is on a permanent trajectory looping between Earth and Mars) you could significantly increase the amount of useful payload you could deliver to Mars and increase the comfort and safety of passengers. Although for bulk cargo you could use electric propulsion to push the cargo out of low Earth orbit over to Mars and then use aerocapture / aerobraking to bring the payloads within reach of an orbital tug at Mars that could bring it to a station where it could be ferried down to the surface.
Back to Martian resources. With carbon monoxide available all you need is energy in order to be able to effectively smelt metals such as iron, copper, or aluminum. Some of the rocks and regolith on Mars are effectively high grade ores, especially of iron. It would not take much equipment to be able to start producing builk amounts of steel. This could be used for all sorts of purposes in expanding a base into a full fledged settlement.
From there things accelerate quickly. It gets easier and easier to send things to Mars, to come back from Mars, and to build things on Mars. Capital investments on Mars start to make a huge amount of sense. A substantial power source on Mars (even just in the single megawatt range) is not merely a lifeline for a base it becomes the seed of a growing industrial base. With power and water you can process the atmosphere and bootstrap the chemical industry with all the products listed above. And with that you can smelt bulk metals, and make glass. You can also start making concrete and other building materials. You can start making buildings and farming structures where only a small fraction of the structure is composed of supplies shipped from Earth.
And that's really just square 1. From there you can move on to more advanced industry, more robust farming, more advanced technology, and so on. The very first visitors to Mars will likely be scientists, but the second wave will be dominated by engineers. Imagine what will be built with the thousands of tonnes of steel, concrete, aluminum, copper, and so forth that will be produced within only the first decade of this primitive industrial capacity coming online. Certainly more than a trailer park in the skies, far more.