Part of the theory also is that this process happened over millions of years. You want to see it happen over a few decades.
So there is millions of years of evidence to work with. Still, as far as I know, no proof of any species evolving into another species based on any evidence. I’m asking honestly though if there is a claim that there is proof one species evolving into another, I have just read that there is none . . . that the “missing link” is still missing . . . for every species on the planet.
Now there’s a built-in defense mechanism if I ever saw one.
“It takes million of years to observe, therefore I win the argument in this lifetime.”