It's an interesting idea. However, just because more people are coding, it doesn't mean that more marketable games are available.
While true, there are also a lot of free games being produced. From GGJ and LudumDare alone, there are 10000 games produced each year. Even if you skim the top 1% quality from those, you still have on average two new games per week to play. Add to this the myriad games uploaded to sites like Kongregate and Newgrounds. With all these free options, a small commercial developer cannot realistically charge much money for small games they release. tl;dr - Free alternatives help to drive down prices.
IMO, the positive result of more people getting their ideas into code should be more diverse and innovative gaming in general as ideas are shared around.
Perhaps there are. Again, if you look at things like GGJ and LudumDare, you will see lots of innovation. But it's rare to see innovation in a commercial setting. I feel that innovation is a small corner of the market. Mainstream consists by and large of what is tried and tested.
Part of the reason for that I've given above: that mainstream audiences prefer to entertain their senses, rather than their minds. Innovation doesn't fit with that; familiar/established genres do.
Perhaps a more profound question we can ponder is why do some genres become commercially popular while others fail to?
IMO, play and learning have a lot of overlaps. No coincidence that established genres tend to be associated with certain skills. eg, FPS games train spatial orientation, agile thinking, and predicting other players strengths and weaknesses from their behaviour.
This learning portion gives games in established genres a broader identity. The trouble with a lot of innovative games is that they can lack this property: They present new mechanics, but not provide much skill honing. I feel it's largely this skill honing that makes play feel worthwhile, and rewarding... and maybe that is what people pay money for?