So here's my take and I know you already made your mind (based on your latest response) but I didn't have tíme to respond before.
One thing that somewhat bothers me about your perspective is the idea that "others don't have to write that well to get reads". That is a very false statement if I may say. Although you may feel like something is mainstream or not unique enough does not mean that the writer didn't put a heck ton of effort into it. If something becomes popular, there IS something there that brings people to read it. Demeaning that and saying that the writers are not good at writing is just diminishing what they are good at.
Yes, popular does not equal good always, but good is subject to opinion. And as a writer, you have to understand the mentality of a reader. The truth is that a basic reader does not care if the writing isn't top notch, this is stuff that critics and other writers notice. A reader just wants to have a good time. I would know this as when I was an avid reader on various sites, I didn't care for typos or wouldn't quit just because the grammar was bad. I was a teenager. Who cared at that point. It was the story and the ideas that had to keep me hooked.
Saying this, should you quit? Well that is up to you. In my opinion, if there is something holding you on this app, then it might be bad for you to leave but I wouldn't know what your situation is. Does your story/writing fit the demographic on here? Again, that is something that you need to decide. If you want to continue on Tapas, then it's perhaps good to play by the rules. Do you want readers but not getting any? Then promote your story. Sorry if it sounds mean but it sounds like you're excusing your own laziness to promote. It's fun, and it's cool to find unique ways to do so. I personally have been pretty bored of the tapas forums recently so I switched to Twitter and so far it's been a much more fruitful experience. Again, it's different for everyone.
We all start at the bottom and from there it's just about the drill. If you want to quit, go for it. I went through the same thing when I escaped the hell hole of an app called wattpad, and migrated to the Chad Tapas app. In my opinion, it is superior, but also fits my story better as I've been lucky enough to get a readership in a MUCH smaller time frame than wattpad. I do consider wattpad as a learning process though since I tried to make my writing as good as possible and found readers there too. It was only when I was sure it was okay enough to post somewhere else that I did so. In that sense you could consider this same thing for tapas if you feel like there is a better option for you. Nothing necessarily wrong about that.
Again, my only issue is with how you compare it to the others. Not saying you can't compare, that IS the point of a competitive app, but once you start diminishing others' success is when I feel like there is a line crossed. Leave if it's bad for your mental state, but don't make it the fault of others' good time.