In the millennial suburbs some people have converted their garages into small indie move theaters with good sound systems and people from around the neighborhood show up to watch obscure movies together and eat barbecued food.

pre-millennial here; we call this a party, rather than a "suburban prosumer boutique theatre".

Why are you quoting a phrase that does not exist in the post you are responding to?

The only person calling it that is you...

Is this actually a broad trend, or more just your personal experience? There is very little that could get me to move back to the suburbs, but this kind of thing is compelling.

Similar to people building a bar in their garage.

You could become the first.