To be fair, Rails now makes it much easier to swap libraries if you need to, compared to how it was at the beginning. I agree that that's something useful, but personally I still think that having a sane reference combination to start from is much better than having to choose everything yourself.
Especially in the JS world, I could really feel a "library fatigue" when I had to evaluate so many different alternatives.
> I still think that having a sane reference combination to start from is much better than having to choose everything yourself.
That's why I'm such a fan of TurboGears - it's an easy starting point, but as soon as you want to step up to making your own library choices it's trivial to do so. I think the key insight is that no-one ever wants to go back to upgrading all of their different libraries in lockstep; a "platform" of libraries that are versioned together is a good starting point but at a certain point in the project lifecycle you want to unlock from that and after that trying to go back to the platform is only ever going to be pain.
Especially in the JS world, I could really feel a "library fatigue" when I had to evaluate so many different alternatives.