She has transformed its ability to get PR pieces printed in a variety of news websites and get those links into HN. She has also transformed the amount of Google employees who respond on HN threads when GCE is brought up in any context. As far as the actual business, this PR piece seems to indicate the main transformation was adding in all of the "enterprise cruft" needed to be a real #3 player and not slip to #4.
They have built a lot of momentum in terms of their commitment to 'enterprise' cloud offerings. Obviously that's not going to happen overnight, but they have some amazing technology underlying and are moving in the right direction.
I think it's because you severely limited the perception to a basic ranking. It's a massive undertaking to actually move up against AWS or Azure considering the incredible scale of these platforms so continuing to be #3 in customers is not really an accurate measure of progress.
The article is pretty clear on what's she's done so far. There's no denying that they have a lot of work to do but if you're actively using the platform then you'll notice that there has been a lot of change in just a few months with them, which should all help to increase that customer number.