It is somewhat surprising that it is widely considered to be most useful filter, yet there is no pre-made filter in Photoshop, or Lightroom for that matter, to apply the said filter post-shoot digitally.
Granted, it is not as good as shooting with polarizer as if the highlights or reflections are burned there's just not enough data to dig out the lost detail. However, part of the damage can be remedied digitally afterwards. And the fact that there's no ready made filter does not mean that the same effect couldn't be achieved with the aforementioned applications, it just a bit harder.
These same techniques are very much usable also when you don't want to use polarizing filter. For example you don't want to use it when shooting multiple pictures to be combined into a panorama.