I guess it makes the previous console and its games to be much cheaper. Sooooo people who havent bought it, will buy it instead of the latest one, which cost more, and have less games available.

And for those people, I would recommend a PC.  So the one demographic that would benefit is not even best suited for consoles in the first place.

5 years is still, imo, spot on. If AAA devs can't make that work, then they need to scale down. You don't need huge budgets to change the world (Minecraft etc.).

From a consumer perspective, longer console lifecycles mean they get more bang for their buck. Publishers and developers prefer shorter console cycles because it allows them to plan ahead more easily. Learning the hardware is no longer much of an issue because the PS4 and Xbox One are basically stripped down PC's. There's also an unwritten rule in the industry where publishers should not introduce new IP's towards the end of a console's life cycle because of a lack of interest in older hardware. This goes into the development planning. This why when we had the unusually long console cycle last generation, publishers were etting frustrated because they did not know when the next console cycle would begin.

Better hardware meaning better graphics for your games

1) that is highly subjective. In fact I would say the longer the gen goes the less it is justifiable to be that much behind current technology.

2) If next gen launches with the same architecture(which is rumored) then it will have full backwards compatibility to this gen, which gives it instantly the better library.

3) That wouldn't be necessary if they were just supplied with easy architectures and more powerful hardware. A thing that could be done with faster cycles.

4) That's Nintendo's problem and has nothing to do with the length of a console cycle.

In fact the only benefit I see for longer console cycles is the small amount of money you save and in case of no BC less clutter on your TV board. Longer console cycles are only beneficial for the console manufacturers and for people who can't do math and/or don't care about visual fidelity.

That's the life span for nintendo consoles. 

If you get a better PS4 right now with the same architecture but beefier hardware all current gen games would run and look better as well as all new ones. I don't see why you would need to fully utilize hardware when you get supplied with more of it. That's like rationing your food when you already have too much in the pantry.

This whole "We need to fully utilize the hardware" is a silly need console manufacturers created by making the cycles longer and as such forcing the developers to come up with new ideas to squeeze a bit more performance out of shitty hardware. This optimizing time could've been used to craft better games. The only one that's benefiting from this is the console manufacturer who gets away with having shitty hardware for a long time.

In most cases I would say no ...

Aside from the benefit of seeing more immediate gains with better hardware which is mostly ends being restricted to the wealthy, shorter lifespans should only be reserved for extreme cases of a commercially failing platforms like Sega Saturn and WII U because likewise they will never have a chance at brand redemption when it comes to consumer views ...

Even then shelving a somewhat recent platform to gain some grounds with a new one has it's own repercussions ...

If you hate shitty hardware so much why even bother with consoles ?