I doubt that this will help anyone here, but there is absolutely a silver bullet, and no one is mentioning it. It's incredibly obvious, and everybody that is winning is doing it all the time. You pay for advertising. It doesn't have to be large scale, you can scale it down as much as you like. It absolutely works, and I've done it many times.
Here is how you can get a million people to watch your short film. First, do your research about the cost effectiveness of the various major avenues as they relate to your target demographic. Then create custom trailers tailored to the respective attention spans of those particular outlets. Those stats can be found during research. Take care to design your trailer to grip fast, within the first few seconds. Don't overstay your welcome with viewers. Be aware of percentages of mobile audiences per platform, those stats are available, and it does make a difference. Design accordingly.
It can be somewhat affordable depending on the result you feel like you need. I spent a measly $1100 dollars on ads for my last film, and called a few tv stations to suggest that they interview me, which they did. The result was about 330,000 views of the trailer, which in turn resulted in enough sales of the film to break even.
Conventional Hollywood rule of thumb is that about half of your budget for a film goes to advertising, maybe 30 or 40 percent in some cases. If the studio wants to tank a film for some reason, to make sure it fails, they will spend about 15% budget on advertising or less, which basically guarantees failure. I would have spent the correct 7k on ads, but I ran out of money, and was lucky to recoup expenses as a result. I should add that my results were unusually good, because I had a solid strategy, based on hyper targeted advertising in a small geographic region where the film was especially relevant. Storefronts that carried the film frequently told me that many customers outright told them that they were hoping to see their house in a movie, and were mainly excited because it was filmed in their home town.