When google came out it had the best algothitm backed by good hardware (as far as I understand often off the shelf hardware - anyway the page simply "just worked"). Difference between google and competitors was like night and day when it came out. It gained marker share very quickly because once you started using it - you didnt have any incentive to go back.

Now google search has a lot of problems, much better competition. But seriously you probably dont understand how it was years ago.

Also I thought that in ML still the best algorhitms win, since all the big companies have money. If someone came and developed a "pagerank-equivalent" for AI that is better than the current algs, customerd would switch quickly since there is no loyalty.

On a side note: Microsoft is playing the game very smart by adding AI to their products what makes you stick to them.