I assumed it came from investors trying to get out in front of a coming trend that didn't happen, or didn't happen yet.

There's a desire by part of the population, including some people who are influential in the culture and politics, to ban meat or make it prohibitively expensive, in order to reduce the load livestock puts on land and other resources. So if you believed that push was going to reach a tipping point in the next few years, where a lot of people who like meat were about to find that real burgers and steaks were out of their budget, you might think it's a great time to get into the fake meat business and be ready to serve that market.

That didn't happen, but I can see why someone might have thought it was going to, or might think it still will.