Retirement savings: How much is enough?

Half a million? One million? Two? What about five? How much money will it take for you to be financially independent when retirement season arrives at your door?
Most superannuation companies have a table in their prospectus' showing the difference between what your retirement savings plan would look like if you started at age 25, 35, 45 etc. encouraging you to plan earlier and put away more. But is this reality? Should I be busting my gut for a period in time where I will have the least amount of energy, possibly the worst health I've ever experienced and by far the least amount of drive and motivation.
But then retirement analysts would argue that this is exactly why we need to work hard now to reap the future benefits. To this sentiment I don't disagree. What I struggle to understand is why people save so hard for a lifestyle that can only be short at best and at worst may never actually eventuate.
Now, don't get me wrong. I'm not advocating the "live-it-up-today-for-tomorrow-may-never-come" ideology. I just struggle with accumulating as much as you can in order to feast for a short period in time. Proper planning is essential it's just the focus that I'm targeting.
So how much retirement savings is enough? By the time you retire, you should have completely paid off your house. In fact, if you took out a mortgage when you were 25 you would have paid it off by the time you're 50 giving you 15 years to supplement your wealth by purchasing another property or investing in shares or other financial instruments.
Your children will have all left home. You should have paid off your car(s). The furniture will all be owned and there are no more landscaping projects to complete. Therefore, your costs are limited to; food, utilities, rates, healthcare and insurances. How much does that cost?
Most people get this bee in their bonnet that they need more income when they retire viewing it similarly to winning the lottery. They dream of visiting Europe in the summer, driving an RV to escape the winter and being able to wine and dine at their leisure. The house they keep will need to be large enough to accommodate the grandkids and they will still need to possess two family-sized cars. What's wrong with this picture?
I understand retirement savings and the government's push for people to have some nest for life after 65. What I don't get is the desire to pass life by in the pursuit of a retirement nirvana.
How much retirement savings is enough? Enough to maintain the lifestyle that I'm currently enjoying.

