It's silly to say Aople is an "idea." Apple would be a footnote in history if not for Steve Jobs' relentless pursuits. GPS and credit cards are ideas, as is Google's PageRsnk algorithm, but companies are not.
I am still using my iPad 2 for web and email and it works great (though iOS 8 slowed it down some what). Yet I replace my iPhone with the latest model every year. I see the iPad as more of a home appliance and I don't upgrade my home appliances on a regular basis. I keep using them until they die.
WordPerfect was years late to the DOS-to-Windows transition and Word took over. Now Word is years late to the Windows-to-iOS transition with a worthy competitor firmly entrenched. Not saying Office will disappear but the parallels are interesting.
Unfortunately if I switch from my 10gb plan to the lower cost 6GB (formerly 4GB) plan, AT&T increases the monthly fee for each of my family's 2 phones from $15/mo to $25/mo. The net result is my bill drops by just $2.50 per month when you switch from 10GB to 6GB. Not worth it.