[Klaus]

https://www.sony.com.au/electronics/camera-lenses/sel2470gm2

[toni-a]

Looking at bthe elements diagram, we can see that Sony moved the elements backwards, which will contribute to smaller lighter lens and better  balance when handling.
If all those elements are fixed relatively to each other that's great, however if they are moving for focus/ zoom, many tiny lenses moving that means there's a danger for acquired decentering or at least decrease in optical properties with use,  this is the general tendancy with all manufacturers and I'm OK with it, but just speculating

[Brightcolours]

There are no modern lenses that have no moving lens elements. Don't think that decentering has to do with floating elements, per se.

[Klaus]

Without having used these very latest lenses - Sony has introduced more lightweight materials with both this lens as well as the 16-35 PZ.
That's nothing new in the broader scope - the Canon lenses are also using plastics.

I reckon it's thermally more stable than metal. Yet the question remains around the long-term durability and whether this is what users want.
But maybe it's just me being German and Germans like tanks.