I understood the transition to be voluntary, and that the WooCommerce Tickets plugin would continue to function, it just wouldn’t be updated.
And I don’t recall seeing anywhere in the release notes for The Events Calendar/The Events Calendar Pro that the updates would not work with WooCommerce Tickets (I typically read release notes pretty thoroughly, though I admit it’s possible I overlooked it).
We don’t have a license for Event Ticket Plus. And while I expected I would have to purchase one eventually, and make the transition, I feel like I’m being forced into it before we can discuss it, plan it, and budget it with the client. It’s very disappointing. :-/