To be honest, I expect that team to be hipchat. They've got cash now since their acquisition, and they're making steady improvements to their desktop app.
Personally, I wouldn't enter this market, regardless of how good my devs or how much money I had. There are at least 3 polished and loved products. The problems you describe will probably be fixed before another team could come in with a good solution.
Campfire is made by a company with a massive and rabid following, and is cross-sold to the users of three other popular products, two books, and a massive blog.
Hipchat is an amazing product which is steadily getting better under the steam of great developers. It is also owned by Atlassian, a company with great execution and a strong track record of successful cross-selling.
So under these circumstances, no, I personally wouldn't enter this space.
Campfire gets a fair bit of attention here, but is unheard of outside the 'startup'/B2B space. The stats they post are laughable - last time I checked it was a few thousand messages a day - which is pretty minuscule.
Hipchat fills a hole as well, but there are literally thousands of different ways to spin 'webchat' and carve a big following out.
60,000,000 messages, over 67 months, works out at 895,000 a month - approx 28,000 messages a day.
Or one message every 3 seconds. Campfire could be run from a single small VPS.
I think it's entirely believable that the usage of campfire is that low. All credit to them, they've managed to get people to pay for something people don't actually use very often.
You can't just average them out - you think they have the same number of customers now as they did when they started?
Let's assume they doubled in size every year - I think that's a good if imperfect approximation. That would mean 30m messages sent this year, 80K sent today. A far cry for "a few thousand".
80,000 messages a day is still ridiculously minuscule. It's a rounding error. Average them how you like. Assume exponential growth. Whatever. It's still around the same number of messages that go on in say a single channel on freenode.
Personally, I wouldn't enter this market, regardless of how good my devs or how much money I had. There are at least 3 polished and loved products. The problems you describe will probably be fixed before another team could come in with a good solution.