Yeah, the issue isn't really that there are no similar services available, it's just that people don't really use those services very much. There are several search engines competing against Google too, but if Google blackballs your site and you're dependent on organic search traffic, you're still going to lose 90% of your visitors overnight.

Internet infrastructure is pretty important, so it's a little more disconcerting to me if some huge percentage of sites are dependent on the same single ISP/datacenter/etc.