I agree with your statements, but I have a question. If I am getting a groupon that gives me 50% off $100, and I actually spent the $50 of which groupon takes

I agree with your statements, but I have a question. If I am getting a groupon that gives me 50% off $100, and I actually spent the $50 of which groupon takes ~50%... at what point don't retailers start offering "groupon like rates" directly to me, cutting out groupon? Sure, many retailers will be too lazy due to the distribution groupon has - but won't there surely be this group of retailers?