Can a surrendered type certificate be reacquired by the manufacturer or by another entity, or is it considered to be permanently lost?
From the FAA point of view, the TC is not lost but cannot be reissued. You have to get a new one if you want to become the new TC owner. Order 8110.120 states:

"The surrender of a certificate is a final action. Once surrendered, the action cannot be reversed. A certificate cannot be reissued to a third party or a former holder. A new TC for the product could only be issued as part of the full TC process with a new application, subject to all current regulations."

I don't know EASA's policy but I suspect it likely mirrors the FAA's.

In addition, your statement that aircraft covered by the surrendered TC are grounded is incorrect. Surrendering a TC does not affect the airworthiness status of aircraft produced under the TC. From the same document linked above:

"The surrender of a TC does not affect the airworthiness certificates of existing aircraft. The aircraft remain subject to future AD actions for safety of flight issues that could affect their airworthiness certificates."