It's a bit like asking if I'd want to use an Ipad 1 which is less than 5 years old. If Apple focused on iterating on iOS 5 and kept it running on an iPad 1, and all the developers in the world were developing for the iPad 1, I think we'd be much worse off. We also mustn't forget there's compounding development. i.e. if you have a 1-year release cycle on small updates (4 -> 4S, 5 -> 5S) and a 2-year release cycle for major updates, you compound developments much faster than a 5-year cycle as you can do mini-experiments every year, see how the response is and act on it. Touch ID is a great example, used as an alternative to unlocking with pin on the 5S, well received, then integrated into Apple Pay for in-store payments, appstore payments, paypal payments etc.
Does that mean we're 'to blame'? Well in a way, yes. But I don't really feel it's a big problem. It's a side-effect of something awesome: new technology iterating fast. If you compare mobile tech between 2008 - 2014, I'm pretty amazed. But you offered a pretty extreme 5-year case. I think most obviously would say no to that. But software problems being deprecated on a 2-year old phone (that should have already been resolved anyway) is pretty weak and I don't think it's got much to do with consumers. That's a business choice for which I think enough resources should be made available to fix, unless it's not important. But we're talking a Voip call for a smartphone here, it doesn't get much more elementary than that. It's just bad practice and I don't think we are to blame for that. I wouldn't expect a Voip call to echo madly from an HTC or Apple phone and then not get fixed in the 2 years after.