I don't think anyone here said it did. A quick glance at the Commitments of Traders (COT) Report shows the majority of trade/volume in these contracts are hedgers and spec funds.It is not 'retail' that drives full size and e-mini index markets.
The question is, why would the CME decide to make a micro contract for the emini-s&p? And why now? I personally think it is because they know Tom Sosnoff is planning to introduce a similar product on his "Small Exchange". The CME could careless about retail traders. They just don't like the idea of Sosnoff making his own futures exchange so they are taking away the one thing that could make it a hit.
My understanding is the "Small Exchange" will be geared almost exclusively to retail traders. Institutional access may even be limited. This is part of its selling point. It will be sold as a safe haven to trade smaller contracts and not get picked off/manipulated by institutions. I think the IEX Stock exchange is offering a similar "safe haven" from HFT by putting enforced consistent timing/speed delays on all trades.
Being shielded from the "big bad institutions" sounds like a nice idea, but there is always someone smarter and better equipped to take advantage of these types of things.
There is actually someone here on ET who is living proof of this. He has done it more than once in his life so far. I am talking about Atticus/Destiero. He took rules focused on retail trade execution and found ways to use it to his advantage with the options RAES Arb. Also, not too long ago he somehow learned that venues that cater solely to low-end retail like Oanda FX and a number of other binary options brokers were mispricing their digital touch options. He then proceeded to be such a consistent winner that his profitability led to most if not all of these places shuttering their retail options products and operations.