This was also true for Microsoft. There were plenty of other operating systems, even PC ones.
I experienced this first hand at a company I worked for in the early '90s - we had agreements signed with many PC manufacturers to include our software (which was a DOS launcher of sort, that -- in those days of Win3.0 barely coming out, was more favored by users than Win3), and then all of a sudden, within 3 weeks, every single one of the manufacturers canceled -- and it later turned out Microsoft just visited each and every PC manufacturer and told them their MSDOS "discount" is going away if they bundle our launcher or anything similar.
In other markets, e.g. Office. in which, at the time, they were not a dominant player (Lotus123 was king, Borland Quattro was a strong player, Excel was less so; WordPerfect was king of pword processing), they actually competed by turning out better products.
[0] http://www.computerweekly.com/news/2240052523/BeOS-will-live...
However, I think this is not comparable to what Microsoft did in the OS business (the story I told, BeOS, DR-DOS, IE Bundling) -- an apt comparison would be if the Google Search Engine had been Chrome only, or mobile Googling was Android only.
Google Earth is a niche product - I don't see how this (or any other less-than-fair Google practice I've ever heard of) can be considered abusing one's monopoly in any way.
EDIT: doesn't make your point about switching search engines less valid. It is orders of magnitude easier to change than an OS. But Google now spans other areas besides search.