You can lay block pavers over a rigid concrete base if you wish, but for a residential driveway, if the sub-base is constructed correctly, then there should be no settlement or channelisation, even with 'large cars'. Mrs Taz has a Shogun and has been parking it on our drive for the last few years - the blocks were laid by me, back in the days before I was crippled, and there is no worrying settlement or channelisation anywhere on the driveway. When I was still working, we had Tranny Vans, 3.5T tippers and even a 7.5T Hiab Wagon using the drive regularly, and it's still sound - all this on a 150mm thick granular sub-base.
There is a move towards using a concrete base rather than a granular sub-base on some residential driveways. This has come about because some numpties are not constructing sub-bases properly, and this has led to the incorrect assumption that
all block paving is prone to settlement.
Laying over a concrete bases presents a new set of problems for the construction and, unless there was overwhelming evidence to suggest that the drive would be subjected to exceptional loads, or that the sub-grade was seriously weak (CBR less than 2%) then I would stick with a flexible sub-base and possibly a separation membrane just to hedge my bets.
To read more about the use of pavers over a rigid base, have a look at the
Using a Rigid Base page.