My reasoning is based on the fact they are selling similar to these in the $20k price range. Buying them means they cost a fraction of employing a minimum wage worker in western countries.
They are embodied AI, so improving at the rate AI is. That is exponentially. Meaning iterations of these may be 32, 64, 128, etc times more powerful in the 2030s, and even cheaper.
I think it is very reasonable to say they will be common in the 2030s.
This exponential rate of progress has been observed many times with different types of AI, here's a recent example of it.