on the other hand, an abstract concept such as happiness may be dependent on factors outside of our control rather than what we have right now.
On point. I think that is because concepts like Happiness are to a large extent all about perspective and individual definitions. For people to whom happiness means having x amount of money, they'll likely be very fulfilled on hitting that amount. Although like you rightly indicated, they won't be satisfied for long because the x amount they initially wanted would've changed, and it will continue to for as long as they live because we humans are just insatiable.
while we can argue that some people have it better than others, life would become a utopia, an unreal place if we had everything.
This is literally what paradise is. So if life became like this, the world probably must've ended and we all might just be in heaven.
Your last paragraph is beautiful