Is this the same as 'easy come, easy go'? That if you get something easily, you will lose it easily.
No, that would be "lätt fånget, lätt förgånget". This one is about how life changes: sometimes you're happy, sometimes not so much. I can't think of an English counterpart right now though.
I did find a source for this saying though, it's a children's prayer: http://sv.wikisource.org/wiki/Gud_som_haver_barnen_k%C3%A4r
I found a site that offers several different translations of this prayer here: http://finlander.genealogia.fi/sfhswiki/index.php/Musings_on_%E2%80%9CGud_som_haver%E2%80%9D
But in this reference again lycka is associated with luck. It is a bit confusing. :)
Keep in mind that this is an old prayer. As Swedish society has gone through secularization, "lycka" has become less and less synonymous with "good fate" or "luck".
'Easy come, easy go' pretty much has the same meaning in English: sometimes life is easy (happy), sometimes not so much. Some might argue that the English expression is more about wealth or success, but in English-speaking cultures wealth and happiness are unfortunately still pretty much synonyms... ;)
After quick search on the internet it doesn’t appear to have the same meaning at all. https://dictionary.cambridge.org/dictionary/english/easy-come-easy-go “Easy” does not mean “happiness”. According to the dictionary the phrase appears to mean that if you didn’t work hard or took risk to obtain something for what others would have to, you will likely not value it appropriately and therefore your chances of loosing it will be generally higher.
I feel like the english counterpart would be "Things come and go". To me, that means roughly: things happen, but regardless of whether it's good or bad, life goes on
Is this just an expression that happens to use går, or is går preferred over åker when used abstractly?
It uses går regardless. Lycka is an abstract thing, it will not ride a vehicle.
Is it not possible that it is 'luck comes, luck goes'? Or am I using that meaning of 'lycka' in the wrong context?
Ah of course. So it's just a matter of it sounds more natural in Swedish to use the definite form, but when we translate it to english we drop the definite because to us the definite sounds very clunky
Life is a pendulum oscillating between grief and boredom, happiness is but an illusory and fleeting sensation.
An important distinction between the words happy and joyful/glad might need to be pointed out. Happy (Lyckan) is indeed based upon hap, or luck. That is, circumstance or luck dictates happiness. On the other hand, joy or gladness is not necessarily conditional. Many people go through horrendous events and remain at peace in their mind. Some say I split hairs, but so be it.