So it doesn't matter on what hardware, if you want bcrypt to take 1 second on modern hardware (for any value of "modern"), you can.
The concept actually makes sense, but it kind of assumes that the strength of the security will be increased at the same rate of which technology progresses, which I don’t think will always be the case. This is especially true when you consider potential “bursts” in computation speed progression.
That being said, I’m not implying that I have a better idea. Running algorithms that take 30 seconds to execute isn’t going to work for logging into your Twitter account either.
Make it 15ms for an attacker and it becomes an hour per account just for the dictionary.
You also can't assume that all accounts are equally valueable. An attacker might very well prioritize some of them.
This doesn't render all of this useless but I think you shouldn't consider even best solutions out there to be anything else than a temporary barrier. It's a good one and you probably will have enough time to change your password after a leak but you really do need to change your password within a week or so.