If I'm doing it myself, a cashier has lost their income, and the company is making exponential income from my do it yourself checkout, shouldn't we be getting a discount?

They always have cashiers at the front usually with little or no line every time I've been there in the last three months so there are alternatives to self check out. That said let's say a cashier makes $15/hr (generous), and it takes 2 minutes to use the self check out even with numerous items, that's at most $0.50 of "lost" cashier wages (although the cashier would see even less after taxes are taken out of their paycheck). If you want a $0.50 discount go rummage in your couch a bit or check your pants for loose change you'll come out richer.

I think you're looking at the wrong way. Prices have gone up on everything. Without self checkouts prices may have been even higher. Just my food for thought.