How am I supposed to work on Indesign and Illustrator though? What about video editing? Animators? Web developers, etc?
Pretty crazy to suggest an iPad is a sufficient replacement for a laptop.
I totally understand where you're coming from and I have an iMac Pro at work and a 2019 5K iMac at home. But the iPad is honestly becoming a device where you can do real work when on the go. It even supports a mouse now, and in my testing, it was usable, especially when customizing all the mouse buttons to go back to home, open the new expose like multitasking, open Notification Center, etc.
As for apps, Affinity makes some amazing apps called Affinity Photo (Ps), Affinity Designer (Ai), and Affinity Publisher (Id) that are both on the Mac and iPad (the iPad version of Publisher is in the works). I know .psd and .ai files are compatible, but I believe they are working on supporting either .indd or .idml. The apps themselves are actually pretty fantastic. I haven't used the Publisher one as much, but if it's as good as the other two, I'm sure it will be great (though it did recently launch so it might not have a depth of features yet). And it all feels so much smoother compared to Adobe. I haven't fully switched yet because I have so much muscle memory with CC, but I'd like to completely switch at some point.
But that all being said, yeah, I'm not ready to trade in my Mac any time soon. Especially given how buggy iPadOS beta is right now. But I think in a few years you will be able to do 95% of what you can do on a MBP, with perhaps the tradeoff being extreme lightweight vs. a reduction in productivity. It all depends on what your'e doing, but I think it would be great for my vacations. I bought a USB-C dock for it though which is pretty sweet. It can read SD and micro SD, has a USB-C and USB-A port, a headphone jack, and an HDMI output. It's designed to be slim and rigid on the side of the iPad, so I can just leave everything plugged into it when traveling and dock my iPad when I get back to dump photos or whatever. I was planning on doing that for my vacation next week and leave the MBP behind, but iPad OS Beta 3 had other plans, lol, and SD cards aren't working right now for me on my 2018 12.9". In my testing on a bigger yet unpowered hub I use with my MBP, the iPad Pro can power a Samsung T5 SSD, a G-Drive 2.5" portable HDD, a Sony UHS-II SD card, and a high speed wireless adapter for my Logitech gaming mouse all at the same time, which surprised me. It can also pass through power to charge an iPhone, but I haven't tested that at the same time.
Anyway, you're right, that guy was completely wrong saying the iPad Pro is the future to replace the MacBook Pro, but I think given some more refinements it could definitely replace a MacBook Air for many users. And honestly, for photography, Lightroom is pretty great on it and will be supporting external drives and works great with Apple Pencil. I think I can work nearly as fast editing photos on the iPad as I can on my iMac Pro, with the benefit being that I can kick back in a hammock or literally anywhere while editing. It will be interesting to see how the platform progresses, but I don't think it can be completely written off any longer for professional work, as you seem to suggest. It all depends on what you do.