The money spent mining bitcoin for electricity and hardware could have been used to buy stocks.

It's not really different, for both mining bitcoins and investing in stocks you need to spend some money. You aren't issuing anything for free.

Is mining Bitcoin still proficient (except for ASIC makers, huh)?

Mining scrypt coins is proficient. I make $400/month with 2 machines I built 6 months ago.

$400 a month for 2 machines? You should be making a lot more... I just got started a month ago as a hobby, using MiddleCoin pool which converts/paysout in Bitcoin, --w/ 1 high-end gfx card(7950), I'm earning 200/month. I just reinvested 700 to start building out my rig, which will have 5x R9 270's and a hashrate of 2250 per machine. I currently make .0125 per khs per day. So this one machine will be worth $28/day.

I do wish I'd held onto my dogecoins though, I would've made a LOT more if I hadn't kept pumping/dumping.

Must be low end video cards. Two 290x GPUs will earn more than that.

Is that number before or after deducing electricity costs?