Personal anecdotes aside, the fact is that the IPhone 6 did generate excitement, and Apple promptly used it to take over the market again.
And personal anecdotes aside, a big problem with the old system of generational upgrades is that people DONT have loyalty when generation shifts. Just look at how many customers changed companies from Sony to MS or Nintendo in the last generation and how many switched back this generation.
So it's not like what you're saying isn't already happening for consoles.
In fact the new system would probably promote brand loyalty since backward compatibility ties you into the platform's ecosystem so you can keep your library of games across upgrades.
But that's the company's problem not the fan/consumer. PS3 fucked up in the beginning so Microsoft and Nintendo reaped the reward, even though xbox had 68% failure rate on their consoles by 2008. Microsoft screwed the pouch on xbox one and PS4 is reaping the rewards. And if NX is something people get excited for, then Nintendo will also reap the reward.
The issues of having people flip flop is because of a company doing something or making something they did not want.
For PS3 in the beginning is was a 600$ console with limited network functions. For Wii U it was the tablet, and continuing of Wii ,along with the library of games outside of a few broad titles people didn't seem to care or want.
Xbox one was they didn't want a box that was all about TV, always online, DRM.
You can't put blame on the customers, the blame is on the company and their product.
If Microsoft just listened and looked at why Sony is selling so well, they could seriously be doing the same thing next generation.
But instead they are going to try something that does not work in the console space as seen in the past. It works for items such as smart phones because there are so many options for phones. People don't mind or care if there are yearly releases of the same phone. Because there are so many options out there, and when it all is said and done, a phone is a phone for making calls,texts and the occasional web surfing.
People are not buying phones to spend 59.99+ every couple months to buy games on them. Gaming on phones is cheap. But if let's say phones were primarily used for gaming instead of just calls, and games cost 60$ + you would see people not buying phones that much.