Very well summarized!
I agree 5 years is a perfect horizon to have in the IT industry. Almost any solution will run another 5 years without updates even if it is not optimal. When you see that things will stop work in less than 5 years then it is the time to start moving.
This leaves IBM about 6 months to give us the signs we want, else we simply have to wave goodbye to the most efficient collaboration platform ever.
We already started moving our client to Sencha ExtJS, but we are still planning to use IBM Domino because other solutions gives a lot of pain that IBM Domino saves us.
Hope has not left me behind yet.