> Is it even possible to create a robot weeder without AI?

No, if you use the AI communities definition "AI is any mathematical algorithm that makes a decision"

In the normal world -

I want a robot that can mow. Cut everything to the ground. I'll get a 10 year old to program the path for it (Or put in any beacons it wants)

Too expensive.

It's not AI, it's the price of equipment. (At this stage, the AI bit's the easy section)

Came here to say this too. Saw Tensorfield (2018) demo'd in Shenzhen a few years ago, nice people. Quick web search reveals ecoRobotix (2018; Switzerland), Blue River Technology (2021; Indiana), Farmwise (2019; California), Naio (France; 2018), HortiBot (2008; Denmark)... there are surely more.