As a gambler we need to learn from others so that we are not going to be a victim of such a big loses. To make money as a gambler is not that easy that is why we must be ready and try many techniques that will work for us as a consistent gamblers. If we try a technique and it does not works for us, then we need to try another one that will work and give us the kind of profits we are looking for.
Irrespective of the kind of techniques we adopted, we cannot avoid going on losses because it's all about taking risk to either win or not, his lesson will go far way in teaching others not to be too forward and also to always considers the tendencies for the risk of loosing the game when gambling because nothing is too sure until one wins, just that he had learnt his own lesson in the hard way makes him share with you all to learn from his experience, some couldn't have.
The key about gambling is having fun, not making money as a gambler. You can try different techniques if this makes you happy, but is not the correct approach if you do it in order to find a system to get sustainable profits that works.
We don't know whether the gambler in the OP lost those 1.4 millions for the shake of fun or as a financial strategy. In the first case, if he was already rich, had his life figured out, and was looking for some kind of excitement, it is ok; but if it was a "double or nothing" bet, it wasn't a good strategy (there is no limit for that:
Martingale doesn't work.
In most casino games, the expected value of any individual bet is negative, so the sum of many negative numbers will also always be negative.
The martingale strategy fails even with unbounded stopping time, as long as there is a limit on earnings or on the bets (which is also true in practice).[1] It is only with unbounded wealth, bets and time that it could be argued that the martingale becomes a winning strategy.