Well, no my analysis points out that the main safety purpose of windshield glass is to protect the structural integrity of the occupant cage -- it can't both protect against outside impact and penetration while also being a soft cushion for peoples heads to impact.
A window could give way in either direction without being penetrated, for example by stretching out and permanently deforming. Risk for people inside is that it would give too much way, so that that pole hits your head.
If it's flexible it's not going to support the roof in a rollover -- the windshield is a structural part of the occupant cage.
"Permanently deforming" and "flexible" are different things. The crumple zone of a car isn't flexible, but does deform.
But yes, this probably would either limit what you can do there or necessitate design changes (just like it would glass with some new properties)