No.
You don’t understand, you don’t know what grandfathering means, and you certainly don’t appear to deeply appreciate anything.
Grandfathering recognises the “long-standing support” of “(y)our most loyal community members”, the foundations on which a business was built. Your cheerleaders. Your passionate supporters. Your vocal champions. Your word-of-mouth marketing. Grandfathering is a marketing expense with conversion rates no ad campaign can hope to match. Passionate users sell products.
Burning these people isn’t as simple as losing that marketing, those once passionate supporters will be equally passionate and vocal critics.
The ill will this has generated will be costing you money long after the cancelled yearly renewals have faded.