This is not a once in a 70 Day chance, if it was we all be hearing about it and everyone would be solo mining... You will need about 17,500TH to be hitting a block every 70days.
You are using a PPS method to calculate the above. Statistically it is what you would generate with the current network difficulty.
Excluding fees/cost/etc and any network diff changes, you are earning 0.00065BTC a day
If difficulty was to never rise and fall, it would take approx 9,615 days to generate 6.25BTC or approx 26 Years.
Here are some numbers and facts to drool over...
Every hash has an equal chance of hitting a block
There is approx. 175,000,000TH or 175,000,000,000,000,000,000 Hash
126TH or 126,000,000,000,000 Hash is approx 0.000072% of the over all hash rate
Remember, statistically speaking, you will never hit a block, but that doesn't mean you will not get lucky. (glitch in the Matrix)
So yes it is a once in a life time hit.
Probably Black Jack has about the best odds for the player out of any of the games, so long as the casino does not further undermine the odds... but even with close odds of maybe 1% or 2% against you, some players believe that they can beat the odds to 1% to 2% in their favor. Black jack sounds much better than the odds being described above.