eBay won't care, if you suddenly quit...they really won't!! I called them a few times in late March/early April, and spent a total of about two hours discussing the dreaded GTC Fiasco, and while they "seemed" sympathetic, there was, of course, nothing they could do about it, except to "take notes", and "pass it along to upper management"...the same old spiel they'd always say. And, when I complained that, due to the GTC, I had only used up 24 of my 250 so-called "free" listings for having an eBay Store, and felt like I was being ripped off, well, you can just imagine that they did NOT like that! So, when I mentioned that I was seriously considering closing my eBay Store, effective April 30th, they pretty much "invited" me to close it. ..So, I did! And, stopped selling on eBay, altogether;...at least, for a while. Ever since my sales had dropped to a piddling two items...TWO...in about seven weeks' time, I figured, why even bother? There's just NO motivation to take pictures, compose ads and post them, anymore, since everyone's listings now seem to be never-ending, and buyers now have absolutely NO 'sense of urgency' to buy, like they used to. Before GTC, when buyers would see my 3-day, buy-it-now listings, they would see that particular listings would be ending soon, and that an item might not be available anymore once it's closed out, and that sense of urgency often motivated them to go ahead and pull the trigger, and buy it. But, not now.. Well, anyway;...on the PLUS side, my flea-Bay fees went from as much as 200 bucks per month (plus the monthly eBay Store fee, of $21.95 per month), down to nothing...nada...zilch, for a couple of months now! ..Ohh, sure, a couple hundred bucks a month won't hurt eBay, but, multiply that by thousands of OTHER sellers' accounts not making them money, due to lack of sales, and you'd think that eBay has GOT to be hurting about now, but;...who knows? Ahh, well.. 
Yep, it seems like they have really been GOING OUT OF THEIR WAY to find ways to drive the small-time sellers like us, right out of business! Before the GTC, I would usually sell at least 3 or 4 items (vintage watches, specifically, the red LED watches of the mid-70's) per week, and sometimes as many as 3 or 4 in one DAY, at peak times, but ever since March 18th, when the GTC started, that number dropped to just TWO sales in seven weeks, so, I just decided to give it up...it just wasn't worth the effort, anymore...and this, after being on here for over 19 years!
Of course, the GTC isn't the ONLY thing that's been aggravating about eBay, lately;...and, just to name a couple, of the many things...their annoying habit of KEEPING 10% of the shipping fee that you've collected, so that you're ALWAYS losing money, every time you ship a package; and then, there's that SUPREMELY annoying decision they made some time ago, to start posting dozens and dozens of OTHER SELLERS' ITEMS, right within your OWN listings, "similar sponsored items" and "other items you may like", like they're PURPOSELY trying to draw your potential buyers away from YOUR listing, and away from possibly buying YOUR item, and trying to get them to buy somebody ELSE'S item, instead?! What, you don't have ENOUGH competition ALREADY on eBay, and now they're showing your buyers other stuff to buy instead of yours, and right within YOUR own listing, the listing that YOU have paid for?! 
