Mining is not gambling, but SOLO MINING is gambling.
Especially if you're mining btc.
This is not true. If you have a big enough farm then solo mining is likely going to have a higher EV then pool mining because you will not have to deal with the risk of block withholding attacks on the pool nor with the risk of the pool scamming and not paying the miners
But 99% of the solo miners don't have a big enough mining farm. So its less likely to profit.
Do you have any stats on this or are you just making up that percentage? Miners have an incentive to do what is in their own best interest because they have ongoing expenses (electricity) and if they are not receiving a large enough of a payout they will not be able to pay their bills.