OK, some thoughts...
1. Yeah, it would be really great if all 23 basses that I own, were perfectly balanced. But... they aren't. Since they're all basses I
really like to play, I just install whatever strap best alleviates most of the dive (or stops it) - and just... play the thing.
2. With respect to @iipopes' post about changing your bass' tuners; certainly a good idea, but... not a cure-all in every case - for every bass. My aluminum-necked Kramer 450B, for example, would dive almost as hard and as fast as it does now, even if I removed it's Schaller M4 90 tuners - and didn't replace them at all. It might take... oh, 90 seconds, to pull my shirt over my head when I let go of it - instead of the 70 seconds it takes now. Which, TBH, ain't much of an improvement. It's the dictionary definition of a neck diver - period. At my age now? No, I can't play it continuously for as long as I used to, but... I still enjoy playing it.
3. I have other basses that most people routinely condemn as divers; Ricks and T-Birds, for example. Personally, I've found that, if I play my Gibson and Tokai T-Birds like a lot of people play them - slung low, with the headstock pointed up toward the ceiling? Not only does the neck dive go away, they're also very comfortable to play. They aren't P-Basses, so... why try to play them like they are? As for my Ricks? Played at the angle I like to play most of my basses - headstock about 15 degrees above the horizontal - they don't dive at all. But, hang them parallel to the floor?
Then they start to dive... IME,
how I play any of my basses, makes a lot of difference on their propensity to dive...
4. Let's face it; there are basses that, no matter what you do, are not - and never will be - "well balanced". None of my violin basses, nor any of my other hollow- and semi-hollow body basses, are. They aren't
bad; and, TBH, I don't consider holding up a neck that "weighs" about as much as an Egg McMuffin to be much of a chore. My long scale hollow-body bass? Well, holding up a double hamburger - with cheese - is a little harder, but... still not much of a problem. If you really want to own, say, a Hofner 500/2 Club Bass? You're going to have to deal with it's quirks, foibles - and a little neck dive. If that's too much for you to deal with? I feel sorry for you; you're missing out on something special...
5. I can understand - and even sympathize - with people who won't/can't deal with a bass that has some neck dive. A professional "busy" player, who's all over the neck for every song - and who has to play for hours? Yeah, I'd probably be less tolerant of neck dive than I am. The music I play, though, doesn't need me to do that - at all. But, if you don't have to play like that, and still refuse to deal with a bass that isn't absolutely, perfectly balanced - no matter how you play it? I feel kinda sorry for you. You're doomed to fish in a
very small pond for your basses. You won't pull many out of that pond - unless you're happy with the same bass in 3 or 4 different colors. And, you'll miss out on playing a
lot of wonderful (but not perfectly balanced) basses. Like most of the basses in my herd...
