Antonyms for the phrase "ushering in" would be words or phrases that convey the opposite meaning of introducing or bringing in something new. These could include words like "phasing out," "eliminating," "discontinuing," "ending," or "retiring." Alternatively, antonyms for the phrase could include words that indicate stagnation or a lack of change, such as "maintaining," "preserving," "keeping the status quo," "repeating," or "continuing as usual." While "ushering in" is often used in a positive context to describe the introduction of exciting developments or changes, it is important to recognize that its antonyms can also represent important actions or values.