I work in IT as well... and due to changing circumstances, I have been without a laptop for more than a month, after being a heavy laptop user with a higher-end MacBook Pro 15.
Now, in a different situation, I use a thin-client console. (windows, boo, hiss... but it I can log in on any thin client in the company and have my tools and interface. Soon to be VMware Horizon and faster/better)
I have my iPhone 6S, and an iPad Air 2 with a keyboard, VM client, and VPN connection.
Aside from my personal preference for my own after hours use, where I miss Mac OS, I don't need it. I will probably get a new MacBook Retina when they are re-designed. I am not so sure I even need a MacBook Pro, if Skylake or Kaby Lake is as good as suggested. I don't need AutoCAD, X-Code, or Photoshop, most of my tools are web or command line based and network dependent anyway, and served from a powerful server infrastructure.
There is a use case for high-performance workstations when high-horsepower end-point software in multiple parallel instances are required. There is also a use case for a portable workstation laptop. But those use cases are not as wide as they once were, and are shrinking, not growing.
Apple has it's hand-off interface sharing between devices via iCloud, but technology is going further than that, toward fully roaming profiles, and virtual applications or even virtual OS sessions, hosted elsewhere, on workhorse servers.
computing power in your hand needs to be good... and do many different things well, but a lot of that is going to become network dependent and hosted. An iPad with a keyboard and/or a pencil, and the right app, can do that, and even pretty well, while being versatile, modular, and even light weight when stripped down for casual use, with still good battery life.
It is going back toward interconnectedness, not individually provisioned hardware. Mainframes and terminals were due to computing hardware being huge, and hugely expensive. Personal computer hardware came along because it got affordable, and people could work independently, rather than sharing limited mainframe bandwidth and processing power. Processing power and bandwidth are now very abundant, and on a macro scale, affordable, and personal devices are more versatile than ever, and the pendulum is swinging back from isolated or simply networked parallel personal computers that have to do their own processing.
Yes, there are reasons I still want a full OS for myself, rather than solely using iOS, with a file system, and better multi-tasking, a built-on keyboard, and at least a port that I can convert to ethernet. But a family member has an iPad pro 12" and a new 27" imac, and there is no need for a laptop, and that iPad pro is just as fast as one, and far more versatile with the capabilities of Apple Pencil, and slaving the device as a drawing tablet to the desktop computer when necessary.
If Apple shocked the world and combined iOS features into Mac OS as a dual-mode interface operating system, and made an iPad Pro that could run that full-featured OS, and had USB&TB multi-format negotiating ports (perhaps on the detachable keyboard section, and that could work as a laptop with a full OS and hardware performance, or detach from the keyboard section as an iPad, and switch to the touch interface mode (and do it better than Windows/Surface, which is probably why iOS and Mac OS have stayed parallel, rather than combined), I would consider that product very highly. I wonder how fast the data transfer on the magnetic smart connector protocol is capable of... could it support thunderbolt throughput to a keyboard/port base... or the port on the screen/main section would possibly become a USB-C/TB combination socket...
Or maybe a MacBook grade iPad Pro (nearly there anyway...) with a stand, that when you stand it up on a desk or table surface, or a magnetic docking vesa mount that holds the pad, it projects a laser and gesture-sensing keyboard on that surface. No keyboard base required, and the ports would be in the tablet device, but a software keyboard isn't always taking up half the screen.
I work in I.T. but I'm not paid to do graphics or web design, so in that sense -- maybe I'm less qualified than some to comment. But I do support people who work in those areas. My thought is, first of all, that yes - investing the most in a high end desktop workstation still makes the most sense. I see a trend in the whole industry where everyone wants to be more and more mobile. They're chasing after the lightweight, slim and shiny, without enough regard to how much performance/power they're giving up in the process. But ultimately, I know I do my best work when I'm sitting in my favorite computer chair, at my desk where everything is laid out the way I like it -- and I have several big monitors, a good full-sized keyboard, etc. If I'm honest about it, I just don't get that much real work accomplished, by contrast, when I'm out and about with an iPad or a laptop. Even when we're talking Internet or network connection speeds alone, it's SO much better to be plugged into a wired Ethernet link from my desktop than fighting with dodgy wi-fi on my portable.
So I lean towards doing things the way you're considering.... I have my iPad Air 2 that I take with me each work day. That lets me do things like read the morning newspaper while I'm on my commute to the office and answer a few emails. If I was an artist and had the new iPad Pro with a pencil? Then I'm sure I could do a little bit of drawing on it too -- at least to get a rough sketch or outline made, to upload to DropBox to finish from a desktop machine later.
But despite also owning a Macbook Pro retina 15" over here, I wind up keeping that guy in the carrying bag, in my closet, quite a bit of the time. I might take that on a client visit or if I'm working on a Saturday in a remote office, doing some network maintenance or what-not. But in a pinch, I could let it go and still be 99% as productive as ever between my desktop workstation and the iPad.
avid Phelan for 
