No.
300MH/s = .67BTC/day
= $5.70/day
= $171/month
And anyone with that kind of MH/s is probably using no more than 250w of electricity, so 180kwh/month, or about $18 more in electricity per month. Well, if you get decent rates on electricity, anyway. $72/month at most though.
Mining is far from being unprofitable. When difficulty hits 4M, then we'll talk about it being unprofitable for a good portion of hobbyist miners.
My margins are much lower but yes i see there is still some profit my power rate is almost double what you quoted for yours and my mhash is more in the range of 240mhash.
Thanks for breaking it down, i feel like it will force some people out but we will see.