Yeah, but who decides if it's a defect? Maybe the defect is subtle and only manifests in rare cases and the upstream rightfully decides that after a risk/payoff analysis, it's not worth fixing it.
Or maybe he agrees and fixes it and it's included in distributions 7 years later.
I've changed 5 jobs in 7 years (because of life circumstances) and I'm not even a job hopper... How is any commercial shop going to plan around 7 year time frames?
Well, within a debian distribution the Debian developer responsible for the downstream package would get the dependency fixed, either themselves or by badgering the maintainer, and use the fixed Debian version. This gives Debian a consistent set of packages that work together. Yes, it's a lot of work and it's why Debian are behind other distributions and don't include Hadoop. But it reduces the unpleasant surprises.
It's effectively part of insisting that it's properly Free software - if you can't maintain your own bugfixed fork, but have to keep going to an external organisation for their version, is it really Free?
Sure, but this should be considered either a defect or something highlighted by a major version number jump.