Last I checked, neither does Greta Thunberg.

As she's the one whose lifestyle you find to be a "serious question", this feels like you're making an "arguments as soldiers" reaction here rather than taking the actual point that it is very possible to live cheaply if this is your goal in life.

> This means you have sufficient capital to sustain yourself this way,

Irrelevant. My income being €1k/month is what matters, not how I get it.

> and probably a place to live with no rent or mortgage. This also means you had either a rich family or earned quite a lot in the past what allowed you to collect this capital.

And in my example I wrote the other person saying "after my mortgage", for a reason.

That aside, it can also mean I live somewhere cheap: I've always been able to live this cheaply, even when I was renting. It's been a while since I was at university so double these numbers for inflation, but University halls were about £70/week at the time for the nice option; the cheap ones (which I was dumb enough to go for in the final year, do not recommend) were £40/week.

I was still paying rent through the pandemic. At every point in my life, when I have paid rent, it has always been low enough that a £1k/m or €1k/m income would have had enough left over for food and bills, yes including during the pandemic. That my income was often higher is of course how the savings I do have, happened.

At university, I made a game of the food options, which was in retrospect not actually sustainable, but what was sustainable last I checked (pandemic) was £1/day. I didn't spend all of my student loan (£3k/year but also that's only spent term-time and see previous point about inflation), even without part-time work at university.

Living cheaply is possible, if that is your goal.

> Well, maybe everyone could decide to grind few years (though in my country the minimal wage is not much greater than your "passive income", so grind options are limited)

She's Swedish, Sweden is in the EU, she clearly has a good gasp of English, so she has many minimum wages to choose from.

> and then decide to not have a family and don't buy a phone.

She's 23. And now you seem to be saying that people shouldn't be free to choose to not have families before turning 23.

Also, there's a big gap between "don't buy a phone" and "spend £50/month on the contract".

> We would then have a whole society of full-time political activists, but then there is a question why any action matters.

I could say this about 100% of professions. Even if we were all farmers, or all poets, or all software developers, or all soldiers. And, of course, politicians, who are, you know, paid to do politics full-time. Or worse, lobbyists, who are what you imagine Greta Thunberg to be, except they wear suits and don't hitch lifts and do get paid enough to support a family.

It's called "division of labour".

> "Oh, they really do not try enough. Just get up earlier and cancel your Netflix sub".

My Netflix example was simply one item on a long, long list. Hence the bit where I wrote about the example person, "spend £2500/month after my mortgage". Because that was what he spent, after his mortgage, every month. On himself. With no family.

This was a real person who made regular trips to France in a huge Lexus and drove without regard to fuel efficiency or indeed the speed limit. They couldn't imagine not spending all the money they spent, having all of the things all of the time. They were also single, living alone in, if I remember correctly, a 5-bed house they owned. They could not even imagine earning less than £60k in c. 2010, when the median UK wages were less than half that (and full-time minimum wages were about £12k) and unlike him those lower wages everyone else had often did support a family.

Overall, a lifestyle such as the visible parts of Greta Thunberg's (I have no idea what her hobbies are, naturally) can be sustained by part-time minimum-wage work.

If her goals in life are to be what she appears to be, that's not expensive, it's about knowing people who let you bunk on a sailing boat for a fortnight; and not a fancy one either, the kind small enough that, to quote: "the Malizia II has no toilet, fixed shower, cooking facilities or proper beds".

If you're complaining that people shouldn't be free decide not to be parents by 23, that people shouldn't be free decide to spend two weeks at a time in those conditions for what they believe in, because *you* prefer to raise a family and find such conditions appalling, that's your mistake, not a "serious question" about her.

Honestly? Your inability to imagine that Greta Thunberg's lifestyle could be anything other than a "serious question" sounds very much like the thought process I saw in my example of Mr. speeding-Lexus-lives-alone-in-5-bed-house, though obviously his specific details were different, he couldn't imagine anyone choosing to have kids for one.