This means that if I had been solo mining this whole time I would not have made one cent yet.
You don't know that. When you're mining something different (like on a different pool), you are mining different work and if you find a block on one pool it doesn't mean you would have found one mining solo. The opposite is also true, you may not have found one doing pooled mining but you may have theoretically found one mining solo at the same time.
Just outta curiosity....What would be the minimum hashrate you would consider enough to attempt solo mining? Luck not withstanding.
There is no correct answer to this. That's a question only you can answer for yourself. The smaller your hashrate, the more you stand to gain by finding a block, but the less you stand to lose - however you chances are ridiculously small. Then as your hashrate climbs, you go into a concurrent rise and fall equation - the amount you stand to gain decreases while the amount you stand to lose increases but your chances climb. For there to be virtually minimal risk you need to average something like 5 blocks every block change which means you need to have 0.5% of the network hashrate or 2PH. Even then, if diff is changing, you need to guarantee more blocks as a whole diff change may pass without you finding a single block so you'd need twice as much to guarantee finding at least one block.
Personally I think if you're not gaining money mining due to not having very cheap electricity, then you may as well be solo mining to have a
chance at making a profit, but then you must accept that you are actually gambling.
The non-deterministic random nature of mining makes it impossible to give a correct answer as nothing can take away that variance.