Lots of duration means lots of overlap, lots of overlap means not much power on low rpms. Maybe you could get smaller turbo to spool up early with big cam too, but it would be a bad missmatch with the engine really wanting to live on the high up but the turbo already clogging it up when it would be ready to go.
It's really that you want to match cam and turbo for the rpm and power you will be using. Extreme power needs more rpm but then you will loose on the lower end.