Especially if people believe, as I do, bonding is built over social interaction, such as talking about the game, or people's kids, or the weather, or a game of golf, or going out and smoking cigarettes. Telecommuting is not conducive to any of that, and for better or worse, networking is best done in person.
Not everyone feels that way, and for a lot of people, especially in tech, it's unnecessary overhead. I hate having to pretend I care about someone's personal life or what happened in sports over the weekend. I do it because it's necessary to succeed in the rah-rah team building world you describe. I would never force anyone I manage to spend time in the office if they could get their work done efficiently at home and preferred things that way. If you're good, and perform excellent work, you don't need to "network" your way to success...that's for people with people skills and not much else. It's like advertising -- advertisers would never have to advertise a product if it could stand on its own merits.
That said telecommuting requires a different level of discipline than the office. I'm sure there are tons of people who abuse it. There are probably also tons of people who use it to provide the flexibility they need. Not being locked into traffic for an hour or more every day is a huge savings in many ways, including your sanity. Being able to disappear for an hour to do an errand during the day, then making it up at night, really helps...as long as you make up the hour later! But tying people to desks or meeting rooms just because networking doesn't really fly in the technology world.