You have zero clues about the relative numbers of iMacs to MacBooks sold. You pull facturds out and post them. I post facts. Replaceable memory on Macs is industry standard and can be purchased anywhere, not just from Apple. I prefer Crucial memory.
With a 3-4 year refresh cycle it’s not hard to figure out.
I put Crucial in my 2011 MBP and it worked fine. The SSD was another story.
The Cable from Apple didn’t have the bandwidth so I had to buy another one.
Then Yosemite killed Trim.