To counter Stephen Elop’s remark that by joining forces, Nokia (NOK) and Microsoft (MSFT) were going to make it a “three horse race” — implying that Apple’s (AAPL) iOS and Google’s (GOOG) Android were the only other viable mobile ecosystems in the running — Asymco‘s Horace Dediu did some digging and produced the chart at right.

It shows the lifespan of 16 major mobile operating systems, several of which have died and two more — Symbian and MeeGo — that Nokia seems ready to put out to pasture.

“What I find noteworthy,” writes Dediu, “is that there is an implied peculiar fatalism about the market when only two platforms are considered viable, neither of which are more than 3 years old. While visiting the Mobile World Congress, I sensed this jumping to conclusions about platforms was eerily similar to that of a few years ago when new entrants like Apple and Google were declared dead on arrival.”

For the rest of his post, click here.

Also on Fortune.com:

• The annotated ‘Tech Supper’
• That old Mac malware canard
• Does Apple have a monopoly?

[Follow Philip Elmer-DeWitt on Twitter @philiped]