The 128gb limitation feels like it's portrayed as a limitation of the M5 chip itself -- not just of the Macbook Air product line.
It is disappointing they didn't up it to at least 256GB on the laptops, but we'll have to wait for the next iteration of the studio to see if they'll give us 1TB unified memory.
Here's holding out hope that we'll still be able to see an M5 Ultra then! :)