I'm no expert but I don't think there's a shortage of experiments that people want to run on mars and the other solar system bodies, especially with sample return capabilities.

We've been launching things into low earth orbit for ~60 years and orbital launch demand still seems to outnumber supply. If we could get our martian surface payload capacity to even 1% of our LEO payload capacity I'm sure there would be many organizations that would want to send something.

Definitely! Just look at all the Cubesat payloads people fly these days - all of that only really possible by the cost of individual satellite mission coming down.

Before that one had to build and launch one big expensive satellite or beg another project to have their technology or experiment included on their mission, with a very limited number of available "slots".

Partially, you can have lots of cheap instruments driving/flying/floating around to find something interesting to look at with the fewer expensive shots.