Don't go to MFL and use their 22's. I did, once. I read nothing but good things about the Ruger auto's, but MFL's wouldn't feed whatsoever. Like, the two I tried wouldn't make it 10 rounds w/o a failure to feed, and then it wouldn't feed the rest in the mag, not until I'd completely empty and reload. Lousy way to spend $20+$16+$5, IMO.
Blazer's are still what, $12/50 or more? I realize that 22 ain't cheap anymore, the brick I bought a month ago was $17/550. Still, that's 10x the rounds/dollar. 22mags are, from what I've seen, not that far off in price from 9mm/38spcl/etc. You're right, it shouldn't take 1,000 rounds to get proficent. But how many rounds/year does it take to stay proficent?
Personally, I think if I get a HD gun, it'll be a 20g. Maybe 12g, but 20g sounds better for me. Straight up less recoil. A 22 makes plenty of sense for my sort of protection away from home--90% of encounters don't require a round to be fired (according to Lott), and I'm more worried about coming across dogs while hiking or bicycling, maybe some ornery teenager. Jungles of Worcester this ain't.
Right now, my allowance for hobbies (which includes shooting) is $20/week. Ammo goes by real quick at that kind of money. I understand your point about more effective rounds, though.