An out-of-hospital heart attack is statistically not survivable. It depends on many factors of course, but being literally hours away from the neatest emergency room (of varying capability) does not bode well. It’s a risk every single passenger assumes when boarding a flight, long haul or not.
Taking a fully-laden widebody into an enroute alternate airport is not without elevated risk for everyone else on board. Some of you wouldn’t make good commanders with your emotion-driven responses. A physician on board and medical advice via satcom would have been taken into account during the decision process. It’s not about costs, but rather, managing risk.