I would expect that if there were a thermal problem, the
solder joints holding the FET+HS assembly to the board
would be the first to let go. Liquidus of solder is well below
any of the other critical temperatures.
Of course once the first leg loses electrical connection,
other badness might ensue (such as, lose the source leg,
immediate gate rupture as the D-B(S) junction is what
shields the D-G thin oxide); lose G, expect uncontrolled
D-S conduction / dissipation.
Plenty of ways to kill a die short of lifting leads or bond wires.