In reality, there are two answers here. Yes, a revocable trust needs a tax ID. But it doesn’t need its own tax ID. A revocable trust uses the social security number of its grantor as its tax ID. A grantor will place assets into the revocable trust, and their SSN will be used for tax purposes. The grantor is still responsible for the taxes invoked by the revocable trust, but the grantor also still has complete control over the terms of the trust and when it is dissolved.
Unlike irrevocable trusts, a revocable trust isn’t going to use its own, independent EIN as a tax ID. Irrevocable trusts need to apply for an EIN (which can be done online, through mail, or through the phone) because they are considered to be a separate entity from either the grantor or the beneficiary. Irrevocable trusts cannot be changed by any of the involved parties without consent from all involved parties, which is what makes them separate entities for both financial and legal purposes. The major benefit to an irrevocable trust is for tax purposes.