Honest question about cartridge vs. turntable performance.

This was a pretty neat discussion before veering into belt vs DD.  A lot of interesting points made.

My own unscientific opinion is that budget carts sound pretty darn good, and like others have pointed out, they depreciate quickly.  And I've heard budget carts really shine with some expensive phono stages (although some will expose their limitations).  So given the question posed by the OP, I'd spend more on the turntable first.  

But as always, a vinyl playback system is just that, a system of a motor/platter/plinth/tonearm/cartridge/phono pre/etc, so it's all about finding the right combo for you.  Tune it by ear and don't worry about where you allocated money.

System synergy is difficult for me to plan so I have made upgrades based on budget and opportunity. I have focused my gear with one brand so I would expect success regarding pre, amp & phono.  I started my love for vinyl 15 years ago with a used Rega Planar 2 from eBay that had the original MM cartridge. I enjoyed if for several years and then got a used Rega RP6 from here with the original HO MM Exact2 cartridge. I was upgrading both at the same time and loved it immediately. I later purchased a used LO MC Goldring Eroica LX that had been retipped with the Sapphire service at SoundSmith. This was a really nice step up. A couple years have passed and I recently purchased a Benz Wood SM new from our good friend Kron here on Audiogon. Okay, my first new cartridge and an obvious step up from all others. This cartridge blew me away right out of the box. The soundstage became three dimensional and so precise! I have been so amazed. I have made other upgrades of components that I will leave out of this conversation, but this was the most fun of them all. I was thinking to start a thread to encourage more newbie analog members like myself to not forget the cartridge. The more seasoned folks realized this long ago.

I will once again chime in with the suggestion that you explore the Well Tempered Labs line of turntables.  Speed stability, inaudible rumble, absolute tracking stability, long-term reliability...all boxes checked.  Mine is the original from 1988.  No plan to change.  

The turntable should be the thing in your system that vanishes and most don't.  Check out anything that George Merrill builds.... http://hifigem.com/
He's been doing this for a long time and there are several informative papers that he's authored as well. 
His all out assault on a turntable that checks all the boxes is:  http://hifigem.com/merrill-williams-101-3-turntable.html
Be careful who you listen to...and best of luck.

Great TT and arm,  Great  Cartridge, Great phono stage = great sound.
But! Nothing will help a bad sounding cartridge.