Some crops adapt very swiftly too - for example by rogueing out early bolting lettuces and saving seed from your row at the end of the season you rapidly produce your own lettuces that won't bolt in your local environment. I don't worry about crosses I just grow a selection of lettuces and save seed in one pot and resow the next year - gradually over time there will be crosses and new varieties, but effectively I am just maintaining my own diverse land race that suits me and my soil.
The state of the seed industry is a massive danger for human kind.