So, I suppose you agree that all humans should have access to the same living standard?

Yes.

So, we give them the average living standard than average Europeans enjoy

Grief no. Rather better than that if we can manage it.

(from your words I assume that you do not agree that scaling down is needed, neither morally nor environmentally...)

I have no idea what you mean by "morally" here: it appears to be a misanthropic judgement on how other people live.

The question of resource constraints is another matter. To a first approximation it seems that a standard of living more-or-less equivalent to mine (probably not with horses though) isn't unreasonable. We drive one small car (which we'd rather not, really) we travel a little, not a lot, we use public transport when possible, we have a modest house, eat well, buy nice things but not a lot of them. Various calculators claim that if everyone were like us we'd need about double the resources we have.

Here's the thing: the system we live in is terribly wasteful in ways I can't fix directly. It takes huge amounts of water to provide us with our tap water because of underinvestment in infrastructure. We drive more than we would like to because the public transport is inadequate. Our carbon footprint is large because fossil fuel power generation was the expedient choice for decades. Efficiency and changing our practices would probably account for half our footprint. The details would change, I suppose, but the standard of living wouldn't drop.

3 billion cars (and the oil to go with it, plus the metals), Ipads, Playstation 3, flight vacations, ...

None of which is an obvious problem if we weren't grossly wasteful.

I suggest that maintaining the current standard of living is neither possible NOR desirable.

Whatever about possibility, you'll find that 95% of people disagree on the desirability.

I remember playing checkers with my grandfather when I was a kid. I now have a Wii. Interestingly I derived more pleasure from playing checkers.

You're playing the Wii with the wrong people then. And confusing tools with experiences.

And what about learning a simple musical instrument instead of listening to the latest fad (mainstream or alternative)? Play it to your neighbours. Play it to yourself. In case of simple instruments you can even learn to build it yourself.

Romantic nonsense.

A completely different view of the world. On what fullfills life.

Go tell that to the rest of the world. They don't want your view of the world, which is the point.

Less Prozac.

Arguable. It always seems to me that the utopias of the puritan anti-technologists are places I'd hate to live. If they'd even suffer my existence.