You seem very concerned with the authenticity of your collection. If it is really that much of an issue, get them graded. Pick a company and send them in. 90+% of the autographs out there would benefit very little if at all from authenticating. Notoriously tough signers, upper tier HOF'ers, and long time deceased players aside, it is rarely worth the money spent. Even at $10, you said you have 10's of thousands of autographs. That is $100,000- just in authenticating/encapsulation fees for just 10,000, plus shipping there, and back, and insurance. You make it sound like you have many more. Who do you think is going to pay $15 or $20 for an autograph they can get TTM for free? or non authenticated for $5? Even 20 or 30 years after he dies, I can't imagine a sudden surge in demand for his autograph. We don't know what the future holds, will PSA and SGC be found to be a bigger Ponzi scheme than Bernie Madoff could have dreamed up? Will they be the only reliable sources? Will somebody come along in eight or ten years that revolutionizes the authentication process and leaves them looking primitive by comparison?
I went to Twinsfest this year. I picked up a 1975 Hostess card of Tony Oliva for $5 (probably overpaid, but the event is centered around the Twins, so most of their stuff was jacked up a bit) Oliva and Gladden were autographing at one of the stations for $20 for the pair, one item per player. I got the hostess card signed by Oliva and Gladden on one of his cards. I'm now in it for $15. I send it to SGC and we'll say I had 9 more cards to send too, (just to avoid paying $11 return shipping for 1 card) That's still $10.65 shipping and insurance, so $1.07/card, $10 authenticating and slabbing, plus shipping there (say $3, so .30 a card) I'm into it for $25.40, if I sell on ebay for anywhere near that, I need another $2.50-$3 to cover fees. That means I need $28 or so just to break even. You have said that SGC items are selling for less than PSA items. Look at the stack of TTM I've picked up from members here: Joe Charboneau, Wayne Gross, Grant Jackson, fred Martinez, Rich Gedman, etc. most of these are $1-$3 signatures unslabbed, you'd have to find someone willing to pay $15 or so for them slabbed, and honestly, I'm not going to spend that kind of money so someone else can say my Keith Drumright autograph is real