I think at this point the best thing to do is be patient, and trust that Los Angeles and Miami are acting in good faith to make the best decisions possible for both their individual elephants and the population. Obviously, decisions have to constantly be made in determining what is or isn't the best course of action, and for Los Angeles the decision now that they only have one cow will likely be a different conversation than when they had two or three. However, none of us know the full medical or behavioral histories of these individuals, or what the wants and needs of different facilities may be, and therefore it is premature to be making a judgement as to what the absolute best decision might be.
Could the veterinarians, elephant keepers, and curators, at Los Angeles, in conversation with the Asian Elephant SSP management team, decide sending Tina to TES and bringing in new cows is the best option? Sure, certainly a reasonable possibility and if so I'd respect that. However, I would just as easily respect it if Los Angeles considers Tina's best interests and decides it'd be irresponsible to send a 58-year old elephant to a facility on the other side of the country and that it is best to let Tina live out her life in Los Angeles. Without knowing Tina's medical history, making the judgement call as to whether a move to TES is best for her individually is impossible. Furthermore, it is possible, given what Los Angeles' team knows about Tina's medical and behavioral histories, that transferring out Tina would not be necessary in order to bring in new cows, certainly another reasonable possibility I'd respect. Lastly, I have no clue whether Los Angeles Zoo has any desire to even breed elephants or not. While from a genetics standpoint breeding Billy would be ideal, none of us know his medical and behavioral histories and whether or not placing Billy in a breeding situation would be in Billy's best interest. It's possible, when considering the big picture, that it is decided placing Billy in a breeding herd is not the best course of action, or that moving Billy into a different zoo's breeding herd, while reserving Los Angeles' exhibit for a bachelor herd or geriatric females, is the course of action that's best to take.
At the end of the day, anything with zoo animals, especially zoo animals that get a lot of media attention such as elephants, are complex decisions with a lot of variables involved, and sometimes I think it is best to just trust the experts are making decisions in good faith and wait until decisions are announced to discuss them.