Rampant sharing of authorship among colleagues in the name of "collaboration". Is not taking part in it a death knell for a future in academia? I am a final year PhD student in chemical engineering. Since the start of my PhD, I was clear on one personal philosophy. I will put my name only on those papers where I have made substantial contribution. And I will put my colleague's name on a paper only if he/she has contributed substantially. That's what collaboration means to me and anything else seems fraudulent.

However, my group members frequently put each other's name as co-authors in their papers even if they work on completely different topics and have no contribution in the paper. Now, this is unethical in my perspective, on the other hand, they have 10-15 papers by the time they graduate which increases their chance to secure a postdoc position or a tenure track position.

My advisor says, granting of co-authorship is entirely up to the first author and she doesn't interfere with the process. 

I have experienced similar sharing of authorship during my masters degree as well. Past PhD members or postdocs were given co-authorship in spite of not contributing anything.

I will be getting 4 (first author) + 2 (co-author) papers from my PhD, which is far less than my colleagues' output. 

My colleagues often say that I should have been more collaborative (i.e. share authorship without contribution) as that would have increased my publication count and helped everyone. I simply can't see myself doing that. 

Have I severely affected my chance of a future in academia by not taking part in the authorship sharing practice?
I can tell you from the perspective of a person who was on hiring committees that these kinds of ethical indiscretions are easy to spot and are not well received. To the point, we rejected several applicants because we suspected they weren’t sufficiently independent after graduation as they weren’t lead authors on enough publications.

First of all, word gets around. If a PI lets their group slap their names on random papers, hiring committees will take notice, and will not take these applicants seriously. Second of all, we ask questions! If you obviously know nothing about papers you coauthored (yes, it’s obvious), that reflects very badly on you. Finally, if I were you I’d emphasize that on the few publications you have you are the lead author. 

That said, your colleagues can partly get away with this: publishing is a numbers game and I don’t know how hiring committees think in other places or fields.