[Serious] Generally speaking, is philosophy a worthwhile subject of study?

[vulcanlogician]

Philosophers are more concerned with principles and truth and stuff like that.

I suspect this is true of a lot of philosophers in academia.

There are many many non-academic, real-world issues which require philosophical thought, however. 

~ abortion
~ capital punishment
~ limits on government / limits on individual freedom
~ right to autonomy over one's body -- Is it OK to choose self-destructive behaviors like taking heroin? Is it OK to change your gender? 
~ Do animals have rights, or is it OK to destroy their habitats for profit?
~ Do religious principles have a place in political debate?
~ Do living people have a moral obligation to preserve certain things for future generations?
~ What should be taught in public schools?

There are many others. (I'm not asking for the answers to these questions here -- only pointing out that to get an answer demands philosophical thinking.)

None of these is likely to be settled, in a particular case, by a professional philosopher. But deciding each issue, even for your local district, demands philosophical thought. And the better the quality of the thought is, the better the decision will be.

All the things you listed could be better understood by a critical examination of principles and truth. And academic philosophers explore all the issues you listed.

IMO, philosophy is not wholly an academic thing. It goes all the way back to Socrates (who had no degrees) and Plato (who practically invented academia).

I do like your general sentiment though. I think "academic philosophy" is only one kind of philosophy. And the academic portion is overemphasized in modernity. Philosophy that happens around Walden Pond may be just as good as that which happens among Stanford intelligentsia.