Even after omitting the very significant cost of tooling (my corner clamp jigs for cabinetry cost half what a GALANT table does), getting good material you actually want will easily hit a hundred bucks for a fairly small, plywood-based desk. (Baltic birch isn't cheap! But it's cheaper than solid wood.)
I would rather own that desk, for sure, but it's not cheaper, and IKEA is pretty amazing at what kind of quality they offer at what prices--sure it's all fiberboard or cheap wood, but it's reasonably reliable and it's impressive that it's doable at that scale at all.
That fact that you can easily spend $400-600 on the wood alone for a new dining table is staggering. (And makes you really, really careful while you build it.)
(My pandemic working-from-home desk was made of cheap box-store plywood, because I wasn't going to splurge on baltic for something that I hope I won't be using in a year. And it still cost what an IKEA desk would cost (but fits perfectly in my space, which is why I made it.))
Price of labor is way less. And so is cost of materials.
The price for IKEA piece was materials plus delivery.
The price for that desk was design, delivery and assembly on the spot.
What IKEA item were you comparing it to?
I need drawers to store stuff next to my computer.
This just to say that YMMV based on the item you buy, where you live, what's your experience with "self assembling" items, etc.
I asked a friend of a friend that's a carpenter and he made way better desk for same amount of money.