> but Google presents an interesting challenge here because the free services die without even trying or offering a paid version. I wonder what would happen if, instead of just axing services, google started charging.

If a free Google service had either the volume of users or the instensity of use that would make it seem viable as a paid service, it probably would either become a paid service or, if Google had a strategic reason to keep it free, continue as a free service.

A free service that gets axed is almost certainly one that it doesn't appear likely enough to Google that it would be worthwhile as a paid service to justify expending the staff time required to design a pricing structure and integrate billing.