To be fair, isn't this precisely what happened?
"Spontaneous" can be defined a few different ways: https://www.merriam-webster.com/dictionary/spontaneous
From the link "2: arising from a momentary impulse" you get the implied meaning from the original comment if you assume standard human experience of a "moment" IE a few seconds or less.
However you could argue that human evolution is but a moment in the scope of the universe.
And then with definition "5: developing or occurring without apparent external influence, force, cause, or treatment"
The only way it wouldn't be spontaneous would be if an external actor (Deity of your choice?) directed human evolution somehow. To say this is debatable is an understatement..
And so we have fun in word play and hopefully appreciation of different viewpoints.
:-)
edit: rearranged for better flow
This podcast episode has a good discussion on the subject: https://universetoday.fireside.fm/745
As to the author's last question of whether such a thing even makes sense at all given those time scales, I don't see why not. After all, once the universe reaches heat death, as far as we know nothing from the outside is going to come along and garbage collect it, so why couldn't it last for an arbitrary/infinite number of years? And compared to that, ~10^(10⁶⁹) years, or ~10^(10^(10⁵⁶)) years, or whatever, is nothing.
Considering the ‘arrow of time’ a function on each microstate lends itself better to ”can” questions.
I think both the author and you are assuming your definition for the arrow is correct.
It is still unknown if the arrow allows any arbitrary state to become another, or if there is a strict genealogy for the change of the state that can be seeded from an existing state that ensures it will evolve into a specific other under some time scale, or whether either of those permit Boltzmann brains, or even if there is some control the state has over itself (free will?).