Which other laptop were you going to buy that supports more than 16 GB? How much does it cost? What's it size, weight, color depth and battery life?
As far as I know, the new Surface Book also only supports 16 GB of RAM. Or the new Razer Blade. The Razer Blade Pro can have 32GB of RAM, but it is twice as heavy and twice the volume of the 15" MBP.
http://shop.lenovo.com/us/en/landingpage/promotions/weekly-s...
Dell Precision and HP EliteBook W series had more than 16GB well before that; several in the company where I worked had 20 and 24GB. Neither was obscure or exotic, both were aimed at the same professional market and were 'standard issue' for the top-tier in many large companies.
Apr 2011 ... the EliteBook 8540w can accommodate up to 32GB of memory
April 25, 2011 ... The Precision mobile workstations can handle up to 32GB of 1333MHz RAM and 16GB 1600MHz RAM
... were (and are) big-ass mobile workstations. MBPr were much lighter and thinner but still super-powerful - there was no competition in that weight/volume segment. Today, with Dell XPS, Razer, Surface and so on (even the Purism Librem is basically the same shape), we have plenty of alternatives in that segment, so there were two options really: move into the Air segment, or raise the bar for performance again. They chose the former, people complaining were expecting the latter.
It's a bit of a hulk being the weight of a 2012 MBP.