I think most of us have been close at times especially the ones who dont have an aviation career in mind.
A lot of motivation is the goal. Like anything in life we have an expectation!
to succeed is an achievement to not succeed is a failure. Succeeding makes us feel good failure makes us feel bad.
We are all driven by wanting more.
I remember the story of the pilot flying a piper cub low level.
He looked up and saw the guy flying a retractable fast single. "If Only I could have that I would be satisfied"
The retractable single guy looked up and saw a turbine twin. "If Only I could have that I would be satisfied".
The twin guy looked up and saw a jet. "If Only I could have that I would be satisfied".
The jet guy looked up and saw Concorde."If Only I could have that I would be satisfied".
The Concorde guy looked down and saw the Piper cub. "If Only I could have that I would be satisfied".
So I think many have that goal of reaching being a PPL which is a costly business. Having achieved that and gone through the Glory stage of puffing out their chests taking friends and girlfriends for a ride the costs and what to do next hit hard.
Also there is the deflated period, we save like mad to get a car, once we get that car and have achieved the goal the whole thing goes flat and we look for another goal.
In aviation that can be an IMC rating a Multi rating a better faster aircraft or a new direction ie into the commercial world.
Aircraft are like any other forms of transport TRANSPORT. They have to be useable, reliable and competative compared to the train, boat, car.
Ie they have to have a purpose. Those who are not mega wealthy I believe loose that purpose, loose that motivation. When they get to the point of thinking "what am I doing here! can I afford this self indulgence a lot drop out.
They drop out because as another poster said life events change or they cannot do enough flying to keep that interest going.
Even in the commercial world there are many times when you think "what am I doing here" ? A load of Hassle, not being paid, more expense, keeping type ratings and licences /medicals going, Bad flights, having to fly when you dont want to, Grumpy customers, lack of new goals! Friends who get killed in aviation.
Then you have a flight which kindles the passions you once had and leaves you with that great buzz at the end of the day.
Then you know why you fly! The more you put in the more you get out is true in anything including aviation.
Pace