Yes, the understanding is that Group Buy participants get in on the ground floor, so-to-speak, they pay the "floor" price.
The expectation is (usually valid) that once those sets get into people's hands and end up on Reddit photos, the desire for the sets will increase, and vendors will sell at 'extras' prices.
For example, JTK Royal Alpha is probably coming soon. There was a GB price, which would have been the lowest price for a consumer to purchase at. Then, some stores [in anticipation of coming stock] started offering "pre-order" prices. This is like a step in-between GB and "Extras." I checked, and the store in my country sells pre-orders at 10% more than the GB price. I figure that the Extras price may be overall 20% more than GB price, the 10% increments. So GB price + 10% preorder price + 10% extras price let's say.
And that's in a somewhat depressed market. During the early/mid months of the pandemic, supply of a lot of keyboard components was in question. I noticed that the extras pricing was significantly higher than GB pricing, like 30% or more. You could hypothetically sell your GB keycaps at a reasonable baseline extras price [not excessive flip prices] and still profit.
Beyond all this are the insane Mechmarket flip prices, which are like 100-400% of GB price, scary prices on EBay too.
So anyway, yeah, progressive markup on the sets, from GB to pre-order to extras to 'flip' prices have been common in the past few years.