Nearly all modern crops are hybrid strains, which means the offspring won't have the same genotype as the parents. This is the real reason why re-planting doesn't work well. It's not anything nefarious.
"Nearly all modern crops are hybrid strains"
This is a "citation needed" situation here, the corn & Canola seed markets are certainly dominated by hybrids but very plentiful drops like wheat and rice are not to the best of my knowledge. If you have sources for this I am very interested to read up on it.