"You spent how much on that cartridge?"

I think it’s cartridge/arm fit that is most important. A bad fit can make the best arm or cartridge not sound good. Followed by cartridge quality being of 2nd importance. Then to me it’s phono stage of 3rd importance. Followed by tone arm next. Then turntable. Then isolation. Then cables. I’m sure some have other thoughts but the above is what works for me. 

My theory is that either the felt mat or the vacuum hold down on the Sapphire, or both, hindered its performance, with an added possibility that the Sota was unstable in terms of speed.  Before anyone takes too much offense, I do believe the modern Sota TTs are much better.

@lewm  Oops, that's a caveat I fail to mention - the older series Star platters (III and earlier) feature short & stiff rubber lips that don't make a good seal. Even back in 2007, my III couldn't make proper seal, and despite the vacuum pump working fine, the un-suctioned rubber lip prevented records from making solid platter contact. I'm not sure if this old lip style ever worked very well, but with age they definitely don't. You really have to either tape it down or cut it off. Maybe that was a partial culprit in your case, or maybe not.

Nova Series V and Cosmos IV and newer use much wider and more supple lips that work very well on all but the most warped records - though you do need to clean them regularly. 

Besides my old Star III (upgraded to Nova V) I've added a factory refurbished Cosmos IV+ (adds some of the new tech from Phoenix Engineering) and it's a wonderful table IMO. The older exotic woods were a lot prettier, though :( This one is an orange-ish walnut finish which is truly the ugliest walnut color I've ever seen.

So, you could try Nottingham Analogue Ace Space Deck table with Ace Space arm and motor controller. Add top Ortofon MC, some $3k-$5k tube phono stage, and you will have excellent sound. I would not add optional thick graphite mat - it will make the table less agile,  Spacedeck was not designed with this kind of record mat in mind. But you would need a good mat, not sure which one would work best.

I myself would do it the other way around. Top Nottingham deck with top arm and much less expensive cartridge, would probably begin with Audio Note MM, it is a refined Goldring 1042. Later might upgrade to Ortofon LOMC and better phono stage. And I would most likely never have to upgrade the table and arm. The alternative - Pear Audio next to the top of the line table with arm with the same cartridges and phono stages.

Here is one thing I've learned, and it applies to equipment, music, movies, food, wine, and the quality of practically everything you buy or do.  Sometimes it's good to start somewhere with reviews, but if you get into something it will quickly reach a point where YOU HAVE TO EXPERIENCE IT YOURSELF.  There is no substitute.  Personally I would rather have 20 quality records on a high quality system than 200 records on a mediocre system.  But that's just me.  For others, quantity has a quality all its own, as the old saying goes.  Go to as many stereo stores as you can.  Listen to as many of your friends' stereos as you can.  Tweak the setup and speaker and listening positions if you can.  Turn up the volume and turn it down, and decide what your true priorities are.  My brother is more into midrange clarity than I am.  I'm more into deep bass than he is.  Nothing much is more exciting to me than subterranean bass (that sounds natural - not like a hip-hop car audio rig that's literally shaking the fenders.)  Go find your groove and dig it.

I’ve had carts worth twice my table cost.

Currently have a Soundsmith cart worth about 1/3 of my VPI table cost.

Both work well.