More search results for the longer tail version. Why?

If you type into Google with quotes "how to make money online" it gives up 129,000,000 results.
But typing "make money online" (leaving out the How to") it gives 17,800,000 results. So a whole 100,000,000 results less.

I would have thought that any post / blog / website / page with the word "how to make money online" would also count for "make money online" because it has those words in it.

But maybe not?

Does anyone have an explanation?
And no I'm not going for those keywords.

I would have automatically thought that it would be easier to dominate a keyword the longer it is. But in this case?

I had a very long tail keyword with fewer searches and I was going to target that first
But then a keyword that is 2 words shorter gets much more searches and has fewer competing pages.

So wouldn't it be better if I'd target that keyword?