The high-end Threadrippers are expected to have a pretty high TDP but there's also another problem. These chips have a massive integrated heatspreader so most existing coolers aren't big enough to cover the entire Threadripper IHS. This shouldn't be a problem as long as the CPU dies are covered by the heatsink, but I still think it doesn't feel right to leave a part of the IHS bare on an expensive chip like Threadripper.
Additionally, I haven't seen any compatibility announcements from cooling firms so you may indeed need a new cooler for Threadripper. By bundling Threadripper with an AIO liquid cooler, AMD ensures everyone can enjoy good cooling on launch day.
As TechPowerUp reports, Threadripper may hit the US around August 9:
This, combined by the dearth of compatibility announcements by third-party CPU cooler manufacturers for its TR4 socket, could be forcing AMD to take steps to ensure that the first Threadripper owners aren't left without a cooler, more so in maturing markets. Intel's new LGA2066 socket, on which its Core X processors are based, didn't face this problem, as it shares its mount-hole spacing with older LGA2011v3 socket. According to the source, Threadripper could be available in Japan on the 10th of August. This could mean availability in the US from 9th August.