What to do with your 600 curiosity rovers on Mars is left as an exercise...
The Lunar Rover that came with Apollo 17 drove 22 miles in a little over 4 HOURS.
As it turns out, humans are the best robots.
If it's simply mileage you want, Curiosity's RTG means it can just keep going for years. With an average speed of 30 meters/hr, I'm not seeing much reason to think that it wasn't capable of covering ~1000km over those 4 years (the LRV, on the other hand, could never exceed 92km, total, before the batteries ran out). But mileage simply wasn't the goal.
We can send probes forever, but when do WE go?
My underlying point is that we have enough data to start making attempts at settling Mars, and once we're there, we'll do more science and exploration than any existing robot can. If you doubt that, then show me a robot that can perform an archeological dig on a fossil site without destroying half of the fossils.
Historically, colonists are self-interested. Typically they want to become rich, or they want to escape poverty or persecution. (Typically they're also poorly informed about just how dangerous their new life will be, and how much wealth they can expect to find, but in this age we shouldn't expect that to last much beyond the first landing). There's no precedent that I'm aware of for people leaving comfortable, privileged lives in mass to colonize someplace that has no wealth.
Apple and Google combined valuation: over $1000 billion
The trouble is there are no new users and new ad impressions to be found on Mars.
For example, for the lunar laser ranging experiment they use telescopes to direct the beam at the moon, but the beam is still 6.5 km wide at the moon's surface.
https://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment
[1] https://breakthroughinitiatives.org/