I have some experience in OTA design for both 180 nm and 130 nm technologies. I didn't see much advantage of using 130 nm, as I had to use quite long channel length to achieve an acceptable gain in 130 nm, so the overall design wasn't much smaller. Power consumption was indeed reduced, but so was signal swing headroom.
I am wondering how does analog IC benefit from a smaller technology node.
For conventional and low frequency circuits there is little benefit. Typically gain is lower; supply voltages are lower also.
Matching don't generally scale with technology nodes, so fur a given matching requirement, resistors and capacitors won't shrink. Active devices will generally also need to maintain the same size.
But most circuits also contain non-analog functions - switches, trims, test modes, and digital functions. These will all be smaller and higher performance (speed, power).
This is all a general trend, but designs may change their architecture to take advantage of smaller geometries - eg convert from matched and symmetrical design/ layout to autozeroed circuits.
