Diesels are hugely inefficient for their size without a turbo (take the earlier Mitsubishi Lancer - its 2.0L diesel put out only 68PS), so its almost necessary to have a turbo. Plus since diesels already have stronger internals to withstand the higher compression ratios, its much easier to add a turbo.
A petrol on the other hand would need major rework just to factor in the turbo and already provides decent power ouput/litre. Although in the interest of even better efficiency, turbo-petrols are gaining traction.
.. if you're blind