A couple of possible scenarios I see:
1. Comcast waits for Sea World to die and purchases land after it's torn down. Merlin buys BGT and starts investing in the parks again, Florida's first Giga, and Lego comes to the parks. Disney builds the Wizarding World of Star Wars and Guardians of Energy
2. Sea World dies, land is sectioned off for housing and vacation homes. Discovery Cove continues on under a new name. Merlin buys BGT and starts investing in the parks again, Florida's first Giga, and Lego comes to the parks. Disney builds the Wizarding World of Star Wars and Guardians of Energy. Universal continues to invest in itself as well.
3. Sea World continues to sputter under Blackstone for a long while, BGT is sold off and bought by Merlin and starts investing in the parks again. Sea World continues to be what it is until the Orcas die
4. idk, they get the hint and start building more coasters and rides at Sea World and start realizing they are a locals park and not Universal or Disney
The two major detriments to Sea World that aren't going away are 1) Brand tarnishing and 2) Whatever they are planning with the fourth gate, and continued additions to the Universal parks already established...I really don't see Comcast or Disney buying Sea World...The benefit isn't there for Comcast and Disney has to fix the parks they already have