What you describe is a classic (no pun inteneded).
I was prolic whilst in bands in my 20's. After that (my 30's) i wanted to just write my songs and record them but faced with the cost of just 4 tracks to tape and no outboard I was frustrated because what i heard in my head i could never get on tape. So i did what you're doing. Jam away , have great ideas but the effort to expand on them was too much (in my mind)
Digital came along and "Bingo" i could do it all and at a millionth of the cost.
However that was not enough so i looked for collaborators to write with. Found a site called Songramp.com and in the last 5 years have written, recorded and "posted" about 30 songs, (only 30 in 5 years i hear you say.....yes but that's 29 more than the previous 15 years!.)
The commitment to finish and deliver for your collaborator is not pressure but you know you have to keep up your side of the deal. It works for me really well. It's an enjoyable pressure too. Also there is a community feel about the site and you meet up (Cyber)with others and you collaborate with them too.
The above point someone made about having goal/ (fame/ recognition) for your art and graft is quenched too, becuase you post the song onto an Open Mic page and people comment and slap your back or critique.
This one is quite a small community compared with what's out there. That's good in some respects (Bigger fish / smaller ponds )
Give it a go. I bet it wets your appetite.
Shameless plug: http://www.songramp.com/homepage.php?userid=16509
My Songs are at http://songramp.com/RonnieG