Maybe they had more than just an idea?
Colour me bitter..but my biggest weakness is that I am not 'technical' enough...but why is someone who has never tilled a field or known the rhythms of growing food in the natural world and knows the diff between dirt and soil be better qualified to make what we need?
And keep us suckling on the giant teat(or whatever) of tech? Like Monsanto does..like John Deere and dmca..we are ok trying to adapt nature to tech. Would tech people dare invent something medical without input or participation of doctors and surgeons? Look at the water..the obesity rates..the degraded soils..the poisons in the environment..that's the hubris of science and tech and the power of $. Because peasants have no value, right? Right now..I would rather be a witch riding a broomstick than a farmer or a fan of science/tech.
Getting into YC does not mean that Modular Science is going to be a success. They still need a good tech team, people with domain knowledge, and a market to sell to. Your farming knowledge is definitely important to a project like this, but there is a much greater supply of it. It wouldn't be that hard to hire a couple farmers to be subject matter experts. It is and continues to be insanely hard to put together a team that can build autonomous robots.
Don't give up on your dream, but you need to realize that a farming robot is technology. That's what you're selling. You need people who can build the technology. Find them and build the company. Make a prototype. Use your domain knowledge to make it better than the competition's product. Don't just be a guy with an idea, be a guy who builds things.
Such robots could potentially improve soil and food quality: they could manually remove weeds, making chemicals unnecessary, and they could possibly also replace the current, heavy machinery that requires large monocultures for efficiency. Imagine strawberries picked by a robot from almost-wild plants grown in between the natural vegetation on terrain that was previously inaccessible to farming. Or growing any number of crops in a chaotic mix on current fields.
I am not worried at all that they will replace the farmer. I just have a dim view of certain things and people that were shiny earlier.
And don't be so bitter, it's not VC's fault that you lack technical skills.
If you want to build robots, you need to have a working prototype to show that you or your team has the technical skills and the passion to build something with your own money to pull it off. That's how you get investors.