Why do cars not use resistive heating on the windshield like they have on the rear window?

Those resistive heaters are much more effective, especially when the car is first started. What reason(s) are there to not use them on the front? My guess is that the heaters are more likely to fail than hot air, which necessitates having hot air as a backup, and if you're doing that, the marginal benefit of resistive heaters is not deemed to be worth the added cost. I'd like to hear from somebody who actually knows the answer(s), though. Thanks!

Edit: Thanks to everyone who answered. This question can be considered closed.

Edit 2: Please do not comment that a specific make or model has this feature. It is not answering the question. It is not helpful in any way.