That's frustrating in its own right, but what's worse is that nobody ever factors it into scheduling estimates. If your team is getting 6 hours of work done in an 8 hour day, that's the equivalent of the whole team taking a day off every week and expecting everything to still get done on schedule. Except it's worse, because it makes you less efficient all the time rather than just one day a week.
On the other hand, I don't think that trying to fit all weekly meetings into a single day would solve the problem either. It's often the case that decision makers — the people you need to have at a lot of meetings — are involved in different areas of a business or product, so they'd have overlapping demands on their time. Where I work, there are a few people who are like this, and their schedule shapes how meetings are planned for everyone else. When any of these people have conflicting meetings scheduled, one or more of those meetings have to be rescheduled for another day.
So now everyone else has 2 half days of meetings a week, rather than one full day. And then, what happens if you learn new information and have to make a decision? Do you wait a week to talk about it? Probably not. So, you'd probably have a couple heavy meeting days, and then a number of ad hoc meetings scattered over the week. This is not the improvement we were looking for, and I think at a certain point the team would just drift away from the initial vision, and settle into the former pattern.
Not saying it's a good thing!