From the Grabber/G-3 experience, some of which suffered from less than stable necks, they wanted to make the neck super-sturdy and stuck in those additional steel rods. That can't have helped with the weight. And they probably were happier for a heavier body to prevent the bass from becoming neck-heavy due to the additional reinforcement. Plus in the early eighties, heavy basses were en vogue.
If I'm honest, I have to say that I prefer a too heavy bass to a too light one - there is something in heaviness that I find reassuring of quality. Silly, I know, but I identify light with cheap, but I'm probably not the only one since most boutique basses end up being heavy (probably due to exotic woods and heavy, up-market hardware).