discovery is build around a concept of long term enjoyment.
in order to gain enjoyment - you need to get a feeling of achievement. that can be achievement in pvp - and the more challenging the pvp was - the better ( especially when you won ) ... or the harder it is to "get what you want" the greater the achievement.
another aspect is competitive achievement....
so it does not only count what YOU had to do to get what you wanted - but also how it compares to others.
if it takes you 100000 hours to get a cloaking device - you may be happy once you have it. - but you are not half as happy if 1000 other players have the same thing.
you are twice as happy when you are "one among very few" - that makes you special. - that
things that come to easily are no achievement - everyone get get that stuff too quickly - some its short in both terms.... personal achievement and competetive achievement.
things must have a challange - must be hard to get. or you won t get a motivation to try to get them. - just not too hard - cause as you say - a game is not meant to become a job.
in that respect we are FAR from what professional mmorpgs do - where the term "grinding" is playing in a different league compared to discovery.