My personal view on this has 3 reasons.
1: Minecraft
2: The age of programmers
3: People are bored with current gen games
I believe that Minecraft has caused a large portion of this pixel style art we are currently seeing. People may have different reasons for this, they might really enjoy the art style, they might want to make the next big thing or they simply want to find out about programming and are inspired by Minecraft.
The age of programmers is likely the biggest factor in why we are seeing pixel art games. I’m basing this point off of an assumption that most programmers are in their late teens+ but I honestly feel that people grew up with games that had pixel art and they get a nostalgia feel when creating their own art.
Finally, I think people are just getting bored of the same stuff we have seen for years. Games are becoming too similar and the market is being harder to please and this creates indie developers to start working on different types of games which fit nicely with pixel art such.
I personally got into programming because of Minecraft and because Markus inspired me. I failed the first time I got into programming as I thought it was going to be a easy thing to pick up and could learn how to do it in a matter of weeks, but as we all know, this is not the case. I picked up back up about a year later and 4-6 months in, i’m still learning so much and about to start my University course on Software Engineering. The art I do (badly) is inspired from the games I grew up with and still even play today(I have an Amstrad and SNES setup right next to me).
All in all I think we are seeing the pixel art due to inspiration from games like Minecraft and the general age of programmers.