Starbucks or study hall?

I had a scene today at a Starbucks. (Not the one shown here.)Despite being well appointed, the geniuses at Starbucks redesigned my favorite outlet in such a way as to provide less comfortable seating and almost no seating for parties of four. So when I and my four friends arrived today, there was only one small table for two available.  I assumed that the girl who was using two tables for her computer, notebook, and single cup of coffee would willingly surrender her extra table, but she didn't. She was one of those arrogant, thoughtless people who feel they are entitled to anything they can grab. Finally, after her repeated petulant refusals, a barista made her give up the table. By then, of course, our group was too tense to have a pleasant experience. But it makes one wonder about Starbucks' thinking. They seem to encourage customers to buy a single cup of coffee and spend hours hogging a table and enjoying free wi-fi. Why? This particular shrew, for instance, was a $3 customers while I and my friends—who come there ever week—are always a guaranteed $40.00 tab. But she wasn't and isn't the only one. Every week there are students or adults sitting for long periods, often with a single cup of
coffee and sometimes a beverage that Starbucks doesn't sell. Where is the benefit for a company that so willingly allows low-profit loiterers to spend hours taking up space writing their friends or doing homework, especially when it provides an impedance to paying customers. What am I missing?