I’m going to define “reward” as “something that has functional use in the game”; i.e., non-cosmetic rewards like gold, resources, karma, gear, etc.
The game philosophy is that everyone – as much as possible – is rewarded for doing what they enjoy doing, and that no playstyle will be favored over any other in terms of reward. If you like to solo, group, craft, do events and hearts, explore, do dungeons or PvP, then you are rewarded (as defined above) more or less equitably without any significant favoritism built into the code.
The whole point of “the whole game is the end game” philosophy is that Anet wants everything you do to be “end game” in quality and quantity; this means that if gathering resources and exploring and killing random mobs is as “end game” as explore mode dungeons and ORR and WvW, then it should offer the same kind of rewards.
If all these diverse aspects of the game do not offer fundamentally equitable rewards, and more/better/superior rewards are offered via some particular aspect of the game, that particular aspect, which will favor a particular playstyle, becomes the de facto “end game” and all other playstyles start becoming marginalized, because “what they can do” is less profitable in terms of reward than what others are doing.
I’ve noticed in crafting that even finding new recipes for the same kind of item gives diminishing rewards. I suspect that any kind of repetitious farming for any kind of reward will be dealt with the same way. This means that GW2 is actually sticking to its “everything is the end game” mentality of keeping rewards equitable for every playstyle, including that between casuals and hardcore players. The farming code provides more casual players with better rewards most of the time they play, and more hardcore players with diminishing rewards for their efforts.
If you’re trying to gain rewards, they become harder and harder to obtain by continuously doing any particular aspect of the game. So, we can say that if you’re playing to max out your rewards, Anet has put (and is still working on) – basically – kind of cap on how much reward you can get in GW2 ( at least for doing the same kind of thing over and over at a sitting). This serves both the design philosophy and helps diminish the profitability of botting.
However, if you’re doing something because you enjoy the thing you’re doing, and not because of you’re trying to maximize rewards, then the fact that rewards are diminished shouldn’t matter. If you enjoy doing a thing so much in-game that you’re willing to spend hours and hours doing that same thing over and over, then again, by Anet’s philosophy, it should be because you enjoy doing that thing, not because you’re trying to maximize game reward for your time.
IMO, Anet is promoting the concept that everything you do in GW2 should be because you enjoy doing that thing, not because you’re trying to get rewards for doing that thing. The game is designed to serve the interest of those that enjoy doing a thing, and not to serve the interests of those that are intent on maximizing rewards for doing that thing. The game structure of “you may or may not get a reward for X”, or" you will get diminished rewards for doing X over and over" demonstrates this philosophy.
This is not a carrot-based, skinner-box game, nor does it seek to celebrate any particular playstyle with superior (or more) rewards. Yes, you can play it that way, and you will get diminished returns for doing so. When you “figure out” how to get more rewards for your time than other players, Anet nerfs it because that is their design philosophy. Everywhere that you expect to get more/better rewards for your time than any other player, you will probably be disappointed, because GW2 is not a rewards (as defined above) based game. It has rewards in it, but it is not designed around rewards as being the reason people play the game.
You might not like that philosophy, and you might think an MMOG cannot succeed employing (and sticking to) that philosophy, but Anet has demonstrated over and over that this is their philosophy, and that they plan on adhering to it. The game is designed to serve those that play for the fun of it over the interests of those who play to maximize rewards.
You might counter that your way of “having fun” is to maximize rewards; you can also say that your way of “having fun” is to grief other players or to grind for superior gear. There are some things that people find fun that are not available in GW2 because those things do not serve their basic design philosophy.
GW2 is a fun-centric game, not a rewards-centric game. If you play MMOGs primarily to farm/maximize rewards, you’re going to be disappointed. For those of us who just play in MMOGs to have fun doing whatever thing we’re doing and for whom rewards are just a secondary bonus for our activity, Anet’s philosophy is the greatest thing since pocketbread.