Like it or not, and whether intentional or not, you always shoot for others.
Very few statements regarding something absolute hold up. I do not always
shoot for others and I think there are plenty of photographers who do not always
shoot for others.. Yes sometimes I do. There are some images I take because I know others will like them. However, just as often I shoot just for the pleasure of shooting, without care as to the opinion of anyone else. That doesn't mean I don't show that image to others and see if they like it, but it certainly isn't the reason I shot it. And that doesn't mean others don't like it and buy it.
As I mentioned earlier, those making a living at photography often are forced shoot for others. For those which it is just a job perhaps they only shoot for others. But I do not believe the two are mutually exclusive, and those who find time to shoot for themselves have opportunity to better themselves.
As far as feedback, if one is trying to improve then the feedback must be from sources that are widely varied, and then the feedback must be taken in context of the skill, opinions, and agenda's of those providing the criticism. I believe if you are trying to sell images for people to hang on their wall, the opinions of an uneducated public is pretty valuable. If you are shooting commercial stuff, I would guess the art director and agencies obtain that feedback, so you job is to give them what they want.