Different cartridges have different sonic profiles (as do all audio components). Depending on your program material, room acoustics, and listening habits, different systems will yield different sounds. The trick, and in my experience, the fun of the hobby is designing systems that delight your senses and allow you to have more meaningful listening experiences.
You may enjoy having several systems. If I’m just potting around the house, I listen to a Tivoli Model 1. If the family is making noise, I slip on some headphones (currently driven by Schiit electronics). Sometimes I enjoy my Harbeth P3r speakers driven by a nice set of Odyssey components. I still enjoy my old Altec model 19 horns driven by the Dynaco S70 I built from a kit when I was a kid. Horses for courses, as they say.
If you are serious about learning how to enjoy this hobby, start with a modest (affordable to you but not too expensive, yet) system, try different things out, and go from there. The Mofi turntable and Studio Tracker is a great start. There are dozens of relatively inexpensive ($100 - $500) cartridges you can try. You’ll probably end up liking certain cartridges better for certain types of music or listening situations. You may end up with something you like better than the others for most situations, and that will inform you as you experiment with different systems. As you gain experience and develop your listening skills, you can be more confident in your purchasing decisions, and, hopefully have more fun and satisfaction listening to your music.
I like my MoFi MasterTracker. It sounds great on my brand new Technics S1200 GR. I liked it better than the UltraTracker on my somewhat resolving system (Harbeths, Odyssey). I have an old Shure V-15 III on a Thorens fitted with a Grace tonearm that is perfect with the Dynaco and the Altecs. Sometimes I will fit an ancient Grado F3+ on the Technics and guess what... it sounds wonderful, especially with my old ’60s and ’70s rock records. I had an Ortophon M5e on an entry level Rega that tracked like a bloodhound and sounded great on more beat up records (that didn’t sound good using the MasterTracker). Years ago I had a Denon 103 on an old Elac/Mircord that was miraculous (and dirt cheap).
Yes, you can spend ridiculous amounts of money on cartridges. I would caution, however, that system synergy becomes more important as you move up the price ladder. Putting the Mastertracker on the Rega RP1 would be a waste of money, just as senseless as putting an AirTight on your MoFi table. I’m sure it would sound great, but you will not be extracting its potential on that table. As a famous rock band once claimed, it’s a question of balance.