If you can convert to all touch input and live with the limits of that type of GUI and what you can't do on the iPad versions of apps (see Photoshop), don't need software for which there is no web based equivalent, don't need things like calibration and color managed printing, multi monitor support etc: it can work.
Some of that info is wayyyyy out of date.
"All touch input" Where did that come from? The iPad has long supported an external keyboard and mouse. In fact they are required to make full use of the Multi-monitor support that is there (see below) even though you said it wasn't.
Calibration: If you have a recent iPad Pro, it will have
Reference Mode just like Mac displays have Reference Mode. It is possible to calibrate this Reference Mode similarly to how the Apple XDR and Studio displays are calibrated. Go to the link above and scroll down to "Use Fine-Tune Calibration". No, it still doesn't support custom profiles, but if all you want is native accuracy you can have that.
Multi-monitor support. This is nothing new, it's been in iPad OS for some time but works better in iPad OS 26. I've already done it with my M1 iPad Pro. I was going to verify it again today by plugging my iPad Pro into my 27" monitor, but then I thought, wait a minute, why dig out extra cables? Instead, I unplugged my MacBook Pro from the Thunderbolt dock where I have the 27" monitor plugged in, and I plugged the Thunderbolt dock cable into the iPad Pro instead. Voila, the 27" monitor attached to the dock lit up as an extended display (I had selected Extended Display on the iPad previously). OK so maybe you want to use 2 or more external displays, it can't do that. But let's face it, most people only plug in 1.
I was able to use all the iPad OS abilities like moving windows between iPad and external monitor, multiple freely resizable windows, etc. The new menu bar in iOS 26 is a big step forward in my view, it is going to open up a lot of apps and makes it SO much easier to find keyboard shortcuts.
Printing at a professional level is still very weak though.
The iPad still can't replace my Mac 100%, but it is so much closer to a "real computer" now. When I was using the iPad with my 27" monitor, external keyboard and mouse, I seriously started to forget it wasn't my Mac.
There are so many iPad debates online right now that are filled with outdated thinking. Folks, when you debate the merits of the iPad, please make sure you're completely up to date on how the iPad works right now, in iOS 26, with the M4/M5 models. Otherwise, severe levels of misinformation are possible, and you don't want it to come from you.
Ironically, pointing out the need for the most recent generations of the iPad and OS to make it work like a device with a desktop OS highlights the biggest limitation.
How long does the iPad exist now, and how long has it taken Apple to get to this point? I´d say way too long.
All debates about the capabilities of an iPad have one simple root cause: Apple´s refusal to equip the iPad with a MacOS, or to make a pen-/touch enabled MacBook. Which they could´ve easily done a looooong time ago.
I'd argue that the biggest problem is the app eco system. Until other software vendors actively support the platform it will always lag. That being said however my iPadPro (and previous iterations before) have access to:
Office software
MS Word, Excel, PowerPoint etc to the extent that these will do most of what people do depending on their level of need. For example I can run my business on this - and I do interchangeably with my laptop (MBP M3Pro) which gets less and less use
Apple Pages, Numbers and Keynote - the same
Photography software
Capture One - coming along nicely now. I can get pretty much do 90+% of what I would on my laptop on my iPad - lagging features are DAM, but that is covered in another app
Affinity Photo, Publisher, Designer - covers all my pixel level imaging needs along with printing layout
Nitro - covers the DAM need and again is improving massively
Adobe - don't use it, but have checked out LR - good, PS less good on the iPad, but I'm not an adobe user
Printing
Epson Print Layout
Works well for my P700, doesn't work at all for my P800 - so A2 printing is a no, but on the P900 is a yes (I don't have one of these) - A3+ on my P700 is fine
Multi-Monitor and others
I use with an external BenQ 27" display, the iPad or Laptop depending is attached via a docking station. iPad has the apple keyboard, but I also use it with my MBP's Magic Keyboard and mouse. External speakers etc etc - the list goes on.
There's other software vendors who don't support the iPad and that's the problem. DXO don't etc
And if we go down the non iPad route, I've read any number of complaints about my PC (mainly) doesn't do this or that with - name your manufacturer of choice for this one.
What the iPad does well is editing with touch - obviously not an option on a Mac, and kind of so so on a surface last time I had one. T
he platform is what it is. It works well for what I want to the extent that my M3Pro, 36gb ram sits untouched most of the time.
Photo editing is done in the main using my iPadPro, Capture One, Affinity Photo, Nitro and Epson Print Layout. And I'd say the editing experience is more enjoyable in C1 & Affinity on the iPad than it is on the MBP - my view, yours may vary
I dip into my MBP for some stuff for work when I need software that isn't available natively on an Mac (Visio and MS Project) unless I can get away with the cloud versions, and since I've picked up a M43 camera maybe DXO for those files
I also use Fuji 100mp GFX cameras and the files are handled smoothly in the software on the iPad - which makes me think my MBP is well over specced - but that's another story...
It has the capability to do many things, it works well for me and others, but that's a personal thing same as Windows vs Mac.
Choice is great though
Andy