My theory is that robot tech will "plateau" and stay relatively stable for decades. Sort of like cars are now. Sure the 2020's cars are different than the 1960's ones, but not a whole lot has changed. Big heavy muscle cars? Ford F-150s :/ Improvements within the existing tech as opposed to an evolution like EVs replacing the ICE.

Why restrict tech advances in robotics? The (hundreds of) millions of robots already made would become obsolete & the billionaires wouldn't like that. Replacing them every decade would be brutal to the bottom line. Plus the higher-tech ones would overpower the existing ones, making robotic security very flimsy.
So, plateau. Plus reality may cause that too. Liquid metal? Nah, unlikely.