I don't think you're expected to carry all 3 products with you everywhere you go. I only carry my phone with me 90% of the time. If I have a presentation to do then I may carry a laptop for group presentations using a projector or an iPad for one on one presentations over coffee. I'd never need to have both together.
At home, I use the iPad for reading ebooks, PDFs, blogs etc. Great for sitting on the couch or in bed. If I'm typing a long email or working on a report, then I'll work off my PC. All 3 devices (phone, tablet, PC) serve different functions for me at different times.