laptops and desktops are no longer needed...
That is a true statement if you don't do anything very demanding, sure you can run a business with an iPad or Android tablet (purposely did not include surface as it has the same functionality as a laptop, just comes without the keyboard). Most of what is needed is looking over analytics, checking spreadsheets, finances, and mostly doing assessments in general. All of this can be done using an app, when you start talking about the things that a business needs to run, yeah... someone's going to need a laptop or desktop. Something that can pack enough power to get the job done and move on quickly.
Are laptops dead, they can be if you can live without the power and functionality that it provides. I can run my entertainment center from my iPad or even my iPhone without much trouble, but I still have my Windows computer for high end games and my iMac for everything else.
I guess you're just looking at analytics and report data, and not actually doing anything to it. For supported software, you are limited to something that has app or you need to login through a browser. How are you going to export data from Analytics, Omniture, Quickbooks, Salesforce, ecommerce platforms, and other systems- and then combine it together. Seems like an awful process on a tablet when you can't have a file system or arrange multiple windows on one screen, select copy/paste large sections of spreadsheets. I work in digital marketing and run an ecommerce business and could not imagine getting half my stuff done on an iPad of any size.
Making presentations for work is also a chore because I have multiple windows open to gather data and assets. Screenshots along would take even longer. I can command-shift-4 and select what I want. On a tablet, I have to screenshot the entire screen and then crop each time.
Sounds like you don't really get your hands dirty if you can "run a business" on an iPad...or you are not running the business.