[PapaBear3625]

If evolution is true, life would have started out simple and then evolved in complexity over time.

The premise is false. We still have bacteria and other single-celled organisms. Evolution does not result in more complex organisms, it results in organisms that are better at surviving in their ecological niche, though the mechanism of less-capable organisms dying off. An organism that does well-enough in its niche will stay mostly unchanged.

[JustSayNoToNannies]

We still have bacteria and other single-celled organisms.

If evolution were true, by now they'd look like this:

[D Rider]

The premise is accurate if you are discussing Darwinian evolution.
Also, the point is the lack of transitional forms supporting Darwinian e.

[Diamond]

...it results in organisms that are better at surviving in their ecological niche, though the mechanism of less-capable organisms dying off.

Characterizing neo-Darwinian evolutionary theory in a way that restricts it to the particular mechanism of adaptation rather than, say, a change in gene frequencies is also a false premise.

Cordially,