I see both sides of the argument.
And, yes, in a perfect world, good service is good service. But, at the same time, you have to expect a level of performance contingent with the job. ...I need to get stuff done at my job; I come in early, I stay late, I do what I have to do. ...I don't work at a sneaker store though, and I don't get paid like somebody who does.
You want the company to pay people extra (overtime) to process orders to help facilitate the quicker completion of these orders, when the shoes would have sold in-store without any extra work? At the end of the day, it's a value proposition to the owners - is the good will generated from A+ service worth extra effort, expenditure, and labor required to provide it? Do they think this will turn into added revenue in their pocket in the long run? That's their decision to make.
Two other quick points -
1. Note that most other retailers didn't even make their stock available for online order.
2. Did they guarantee a "ship by" date? (I'm not sure). If not, what are they really slacking on? You can break a commitment that doesn't exist in the first place. ...Can we at least wait 7-10 days before we start complaining.