I have spent many hours writing proposals to people who never even respond. MOTHER***KERS; LOL!!!
The truth of the matter is that these people probably receive a lot of proposals and never even read your 2 page proposal.
THIS IS HOW I DO IT THESE DAYS? I write A 3 to 4 paragraph brief of the proposal. Briefing them about the idea and ask whether they would like to get involved. Then I paste it in the body of the email (not as attachment). In that way you are allowing your audience to skim gist of your story firsthand.
This way seems to be working in getting me replies. Giving the reason why they would not pursue it. Or liking it and requesting a meet or a detailed proposal.
ALL THE BEST!!