In my personal opinion, I think that not only just trading, in every sector every kind of job is not for lifetime, because after a certain time we are forced to retire from all jobs. And that is our physical aging.
But an interesting thing about trading is that if you spend enough time on it and become a master here, then later from here in a very short time you will be able to build a large amount which will help you in a common job like people retire after 50 years of age, here you will be able to retire before that. And you will be able to enjoy the rest of your life comfortably.
True, all sectors have limited time keep working and there are not guarantee would be job for life time although you are working at offline job, your age have most important influence keep working at any company or not after age over you will sacked from any real job. But in trading indeed many people make its not for lifetime job during earn much profitable and supported enough capital you can work without retire or sacked.
So manage well with money management by saving as much possible with profitable and enjoying later after old age, you can life with financial freedom at your old age without have working hard but trading not spent much power, time and you can trade anywhere during have good internet access. For me, trading could be lifetime job during can manage well with profitable and capital if one day later have losses but still have enough fund to buy back or start trading back.