It's only maybe the last 10 years that it has become more of a thing. I think before, most people didn't think about. Most instruments were heavy, and it was just taken as a given. Now we have options, and people that have experienced how great it is to play with a well balanced and lightweight bass won't go back.
If you have a bad back, or shoulder problems, it's a life saver. Even if you don't, but spend hours standing at band practice, it makes a huge difference.
I see heavy basses and guitars as another "traditional" thing that needs to die. Tonewoods are a myth on electric instruments. Unfortunately, people buying guitars love traditional designs, no matter how inferior they are. For example, Fender's bent plate bridges. They're are a pain to change strings, and about as cheap as can be, and yet they're found on $2,000 basses. Same goes for the giant heavy steel tuners, that weigh down the headstock making the bass balance poorly. We know better!
A heavy bass is something that can be easily avoided, so people that know it's a problem for them are going to ask. More people are asking now simply because more people know there's another option.