Search engines? At least 5 that I've used. Google Bing ddg Baidu yandex. Cost of switching is like 10 seconds.
Phone OS? 3, one of which is literally open source and used by a bunch of other competitors. Cost of switching is about $150 and a day.
ISP in the US I have actually no choice. I'm crossing my fingers that CenturyLink or municipal fiber will become a thing, but I ain't optimistic about it. Cost of switching if there was a second one would be around $200+ for modem, installation fees, etc, and last time I did cus I moved it took like a week.