Hahahaah good one 
But lets be real people who dont suport GDKP they also need to ask themselves why you care how someone will play a game? Why you r in need to dictate someone how will play their game, or spent their time in game? Or waaait for it… How you can measure what is fun for someone? 
I dont do Gdkp but also im not selfish and jelly in a same time and spent hours, months in discustion in lfg chanell or trade how GDKP is bad instead to not care and play a game kekw
I went yesterday in Pug ms/os run was pretty much demonic run i spent 20 elixirs, food whole set arrows , and raided with the worst players on server Gnomer 3h I did not get any loot, spent gold on repairs, lost consumables which should last prob over one month with good grp.
Maybe for you dont mean nothing but for someone means everything and they found a fun in that, do insane dps and have great logs.
You r probably player who even dont have elixir in raid, food or bearly wb but that is fine for you but for someone is not You also dont log any raid I wonder why is that.
GDKP is fine, but not like they doing on wrath forexampel. With pumpers and buyers and 80/20 split. Cuz that isnt a gdkp only a boost.
You are right about the reward and fun stuff, but this should be considered not only because of GDKP, just think about all the speedruners, ppl who buying gold/boosts etc they all just want to skip content and go for the reward instanly. Just like ppl in BGs who leaving instantly after the enemy cap the first flag on WSG forexample.
Its not only about gdkp its about the fashion players, they dont like this game they just playing because its hyped.
Because you know someone need to organize that run make sure run will pass smoothly even with naked people. What is point of GDKP if you will not be able to pass 3 boss. Making GDKP needs time is not 4 min job take all who w you without checks etc.
People will always buy gold not matter is there gdkp or not and spend it on other stuff or just pay ingame stuff with real money. You cant control that.