Let me start by saying that no Heat fan wants to see Bam getting traded. But if we are being objective (and leave emnotions out) there is no way Miami can compete for a championship with Bam in his prime.
Bam can't be a number one option and the heat does not have assets (players or picks) to trade for a star who could be that number one option and make them compete. And given his play style, relying mainly on athleticism, the Heat can't wait until their own young players develop since they can expect Bam to be the player he is now in 3-5 years.
Nobody wants their team to suck, and this is not the Heat MO, but the way this team is constructed (and comparing with other teams in the league), Miami won't get close to a championship in the next 3-5 years and here is where the idea of rebuiling makes sense.
Would rather not win a championship but at least be able to load on draft picks and have the opportunity to build a talented team through good draft picks, than being stuck as a play in team or a early round exit in playoffs.
Miami options are:
Being a mediocre team hoping a superstar asks to be traded to Miami and that the other team accepts Miami's lowball offer while wasting Bam's prime
Move Bam and Jimmy to start building a young team around Tyler through the draft.
**Tyler is not a player you build around but he is still young and can be the main guy while this teams rebuild. He could eventually be traded if the Heat can get a good return