Your argument is flawed. The part about kiosks being cheaper over time is correct, but consider: An increase from $7.25/hr to $10.10/hr, assuming they do not allow overtime, represents a gross income increase of $5,928 per year.
($7.25/hr x 40hrs/wk x 52wks/yr = $15,080; $10.10/hr x 40hrs/wk x 52wk/yr = $21,008; $21,008 - $15,080 = $5,928)
McDonalds is a corporation, and we can assume that they have accountants who are good at math. Those accountants know that $5,928 is the smallest yearly number up there. $15,080 and $21,008 are 2.5 to 3.5 times bigger. Why not get rid of the bigger cost? McDonalds will install kiosks because they can cut $15k from a store's yearly labor cost, not because another $6k makes burger-flippers to expensive.
In other words, automation is inevitable, because it lowers cost and increases productivity, which increases profitability. Raising the minimum wage just lowers the time until they realize a return on their investment.
Ever notice that even the busiest people are never too busy to tell you just how busy they are?