Need for mail clients in the future?

Last Week Mozilla span-off Thunderbird as a separate organization concentrating on communications and mail software.

This organization will start work from the Thunderbird code base and work themselves up from there. What I found most interesting from this move was how Mozilla is building on the assumption that people will need a desktop mail client still in the future.

In the future with connectivity becoming ubiquitous, wireless bandwidth not being a bottleneck, and browser based mails expanding through different technical enablers into offline mails also, is there really room for mail clients? We are so locked into Outlook at many work places, that now it might seem so, but what is really the reason for having an mail client compared to the webmail's services we have in 1 year?