Honest question about cartridge vs. turntable performance.

I’ve been a vinyl lover for a few years now and I have an ortofon black cartridge setup with an mmf 5.1 turntable with acrylic platter and speed controller. My question to all the vinyl audiophiles out there is this. How much difference does a turntable really make compared to the cartridge? Will I hear a significant difference if I upgraded my turntable and kept the same cartridge? Isn’t the cartridge 90%+ of the sound from a vinyl setup? Thank you guys in advance for an honest discussion on this topic. 
Thing is, turntables don’t wear out after 1000 hours. Neither do tonearms. So look at TT, tonearm, and cartridge costs over 10 years.

For the record, I had a 10K belt drive TT. Then I built my DIY air bearing TT. Same tonearm on each table. The air bearing TT sounded far better with a budget cartridge than the commercial TT with a higher end Koetsu. Wife agreed. But DIY TT + Koetsu = heaven.

Also, that Koetsu takes real trouble to set up optimally, and a lesser tonearm can’t do it. It's a matter of alignment, which requires both stability and the capacity for fine adjustments.

Finally, before you spend big bucks on a cartridge, try to make sure that your stylus wears slowly. That means ultrasonic record cleaning and strict record hygiene. I do both, and my Koetsu stylus has minimal wear at 1000 hours. If that’s too much trouble, then definitely do not spend serious money on a serious cartridge until you win the lottery.
I agree with Lewm about the cartridge / tonearm combination. Also, that TT's are pretty much independent of either.

So why not spend the money where you can be sure of good results? That is, the TT.

aj523   I agree, I have up grade my REGA RP6 with: New mat, Sub platter, and conterweight; using a Dynavector DV20 x 2L and a Clearsudio Basic + phono preamp, with great succes
New speakers you want to hear a big difference...
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.