You're not talking only 200kbps, you're talking about 25 kbps per person. 25 X 5000 people per server (avg) = 125,000KBPS per server. Even if you estimate only 50% actually use the in game mic function that's 300,000 people each drawing 25kbps. that 7,500,000 kbps minimum in additional bandwidth you need to have available at all times. Sure, you won't have all of the population on at all times but the issue is you need to pay for the bandwidth and have it available at all times. I'd much rather have the consistent updates and server maint as opposed to them spending on in game chat which, lets face it, is just a breeding grounds for trolls.

Also I'd prefer not to hear the hundreds of RMT in the chat channels "BUY THE GILS FOR CHEAPEST PRICE!"