Let a Million Flowers Bloom

Of course we could have a Parliament instead.

Having many candidates from the same party enables the party, through debate, to develop a progressive vision for the country, the nation.

This would require suppressing personal advancement for the good of the group.

But this makes it possible for more interests in the country to make their case for how the country might conduct its business; to arrive at a compromise with a promise of future negotiations to arrive at a society that can live together in peace: arrive at some kind of equilibrium. 

This means that the so-called "debates" a way for each "candidate" to present to the nation their vision of a perfect or at least desirable world or nation ... and get the nation's reaction and opinion on that vision.  Very optimistically. 

Greta Thunberg sailing across the Atlantic on a zero-carbon boat is, at one level, somewhat ridiculous, but at another, possessed of deep and powerful metaphor and symbolism.  One way to think about it is that it is only the First of Millions of zero-carbon voyages.  In other words, it has to start somewhere.

On the other hand, even though we manage to pollute ourselves to death (global warming is a response to pollution) that does not mean that "it ends".  Life will go on; possibly even human life; if it is able to adapt -- evolve quickly enough to thrive in the changing environment, whether the population can adapt to the environment.

The two views are not incompatible.  In fact, they are restatements of the same thing.