If You Lower Prices For New Clients, Do You Offer It To Existing Ones?

The Situation
When your company’s product first launched, the market was wide-open and you were able to sell at a high price point. Over the years, the market has become commoditized as several competitors entered the scene. The competition has slashed pricing to gain market share.
To even have a chance to win new accounts, you are selling at 30% lower price point than you were before. However, you still have many long-term clients buying at the original price structure.
Your Challenge
Do you contact current clients and reduce their pricing to align with new ones? If so, how do you deal with the revenue (and probably profit) losses?
Do you keep your fingers crossed, hope they won’t notice and leave their price as it is? If so, what do you do when they notify you that they are leaving for a lower price elsewhere?