Why are airliner cockpits not shielded from lasers?
Money aside there is a bit of a practical reason as well. One of the simplest ways to protect against lasers is by filtering it using glass of a particular color, depending on the laser we are talking about red or green glass (and some other colors here and there as well). Generally they look something like this 


Coating an airplane windshield in glass of this tint, or a green tint would potentially impair the pilots ability to properly view PAPI or VASI lights which require red/white or red/green differentiation. 

 

It would also cause the pilot to perceive all lights (during a night landing) differently.