Apple overcharges for iMacs with more RAM. There are no two ways about it. While they're by no means alone in this practice (looking at your, Microsoft) and have left upgrade options open-ish on some models, there is no denying that Apple charges users through their noses for getting more RAM on their iMacs – specifically the 21.5" iMac.
"The 21.5" iMac is capable of handling 32 GB of RAM, but each of the three 21.5" iMacs come with a base of just 8GB...the mid-tier model, which costs $1,299 is "configurable to 16GB," for an extra $200...the top-tier 21.5" iMac starts at $1,499 and is "configurable to 32GB." To upgrade that model, you have to pay an additional $600. So the cheapest iMac that you can buy with 32 GB costs $2,099 direct from Apple. That's nonsense because the mid-tier iMac can handle 32GB of RAM, Apple just won't sell it to you that way. And you can buy 32GB of RAM from any number of places online for about $300. This is all a long way of saying that it's possible to upgrade a new iMac to 32GB of RAM for $300 instead of $600 (plus the $300 extra you pay for the top-tier model)."
This is the hypothesis outlined by Motherboard, who tried to pull off a RAM upgrade on the new 2017 21.5" iMacs. Unlike the 27" iMac, these do not have a RAM door at the back, meaning you need to unglue and remove the display, dig through an endless sea of power connections, an entire power supply, and a logic board full of delicate components to pull off an upgrade that iFixit describes as "potentially dangerous". Because it is. One wrong move and you could have just poured $1500 down the drain. Apple doesn't want you to do this, so they can grab more of your hard-earned cash. Which sucks.
While by no means is it impossible, and as Motherboard conclude "Any idiot can do it, but it's frustrating. Progress was slow, but progress was occurring, and none of it was actually difficult", it is several orders of magnitude more difficult than any ordinary RAM upgrade on a normal PC, or even the upgrade on the 27" iMac. This sort of anti-consumer behavior is only irksome for users and enthusiasts, and we can only hope that Apple gets their act together in the future. You can read more about Motherboard's investigation here.
What do you guys think? Will you try upgrading your iMac's RAM? Is it worth the hassle? Do you think Apple will continue with practices like this, or will they see the error in their ways? Let us know in the comments, or post over on the forums with your thoughts.