As far as drug interactions go, they could probably come out with computers to do that, seeing as they've got computers nowadays for everything. And as for the other tasks mentioned, they are not limited to pharmacists. Before I looked into the profession, I also believed that pharmacy was a useless field. I don't know about clinical pharmacy, but as far as retail goes, were it not for laws mandating that pharmacists alone are responsible for dispensing, counseling, etc., the chains would have replaced pharmacists with pharmacy technicians a long time ago.
On a side note, I also think that general practitioners don't serve much use in society, either. In fact, my doctor had to go look something up in a book because she didn't know how to deal with something. I could've done that myself. If I had a real problem, I would go see a specialist. If I want a physical, well, any old geezer can check my blood pressure and send me to the lab for a blood test. All the white coat really shows is that you've been through more schooling than most people, and accordingly, you need a higher salary to pay off those college debts.