Reading this is surreal, like Opposite World. You are selling me on quiet, wifi & power, at the price of your fancy coffee (and preferably even real food), so I can work/read/study in nice atmosphere. Why else would I tolerate paying nearly $6 for a latte and $5 for a muffin? If all I want is to get coffee itself and immediately hit the road, I can go to coffee stand or vending machine.
"Your $3 coffee doesn't entitle you to sit for an hour." First, perhaps I'm typically more than the average user, $3 coffee sounds either horrid or a miracle. Second: Why not? Isn't that the whole point? You're luring me to come in & buy your wares so that I get the benefit of sitting for a while and do my thing, whether it's read a book or work on my laptop.
To the people who see silence & laptops as bad in and of themselves: who are you to prioritize talkers over non-talkers? In my mind and those of many near-university dwellers, cafes are precisely for sitting, reading, working, not for having (sometimes loud) conversations that disturb those around you.
Finally, I'm not aware of "taking up space", as there are typically multiple empty tables at the (independent, non-Starbucks) coffee shops I go to. Maybe this article applies to high-volume areas & times, but I'm not interested in such places anyway.
TL/DR: If you ban people working and studying on laptops, that will just be even less revenue for your establishment, because that is the only reason many of us showed up. Ration out the wifi with time limits and access codes on receipts if you like, I'm fine with that, otherwise just be happy I'm there rather than having yet another empty table.