Indeed. I did Heathrow – Jakarta non-stop earlier this year, a 13h 45min flight. In economy. I don’t claim to have felt 100% at the end of the flight, but nor did I feel particularly bad. I could have put up with another 3 hours, no problem.
I assume that was with Garuda on their new B777. They are a Skytrax 5* airline and their B777s are in 9 across configuration which would have given you a comfortable journey. Try it in the middle seat in a sardine can configuration B787 on a lesser airline and I doubt you'd want to repeat the experience.
Some airlines have a special storage area on their long haul aircraft to cater for deaths inflight.