SpaceshipTwo is considered the 'simplest' and 'safest' of all the upcoming manned commercial vehicle. It has many features that should help keep it reliable. For example, instead of a real liquid rocket engine, it uses a hybrid engine; it has almost no moving parts apart from a valve or two. No turbopumps or gimbals or much mechanical stuff to go wrong. It only goes suborbital, so it does not need a heatshield because there's no re-entry. The landing system uses wings & wheels similar to any commercial jet. This stuff is mature and tested.
In fact, the only novel thing about SS2 is it's wing-feathering system. It's lets the craft to descend vertically still under the pilots control. I wonder if (and this is complete speculation) there was a problem restoring the wings to their 'atmospheric' flight position which prevented them from landing normally.
The consequences for commercial manned spaceflight will be quite severe, I think. I imagine that many Virgin Galactic customers will cancel their pre-orders. The flight test program is dead in it's tracks at this point; even those who don't cancel will be unlikely to fly for many more years while investigations and improvements are concluded. Other manned providers such as SpaceX and XCor will likely be extra cautious before allowing people to fly in their vehicles.
The image of manned commercial spaceflight will take a hit. If the 'Safest' of the commercial vehicles can crash before it even enters service, I worry that many potential customers will be put off. It never hurts to remember that Spaceflight is a dangerous business.
It's a sad day to top off a bad week in spaceflight. :(