Mt gox 2014 incident

[vapourminer]

That time, there was no adoption of cold storage

There was.
The essence of cold storage is keeping the private in a way they can't be accessed  via the internet.

yup, thats where the recovered btc came from; it was on a thumb drive they basically later found somewhere.

[PrivacyG]

But how could hackers steal that much bitcoin back then but not today like mt gox 2014?  Arent hackers employing better hacking techniques today than in 2014?

But can we rule out the possibility that future hackers could pull off a massive bitcoin heist in the distant future??

Once again.  It has no thing to do with Bitcoin but with how secure the platforms really are.  Bitcoin itself did not get hacked.  Ever.  Platforms did.  Yes there will probably be a massive heist at one point in the future, it only takes the right vulnerability in the security of a platform.

[Alphakilo]

When 850000 bitcoins were stolen on mt gox back in 2014, who was the true mastermind behind such breach? 

The true masterminds were Alexey Bilyuchenko and Aleksandr Verner, two Russian nationals.  In 2023, the U.S. Department of Justice officially unsealed indictments against them. 
https://www.justice.gov/archives/opa/pr/russian-nationals-charged-hacking-one-cryptocurrency-exchange-and-illicitly-operating-another

Were all 850000 bitcoins fully recovered? 

No.  The vast majority of the stolen Bitcoin is gone forever or liquidated a long time ago.

A direct answer like this is just on point and hits the nail on the head.
It was a very wild experience in that year and so many investors lost their funds but some were actually recovered after Mt.gox filed for bankruptcy. It was about 200k worth and was in an old forgotten wallet format.
It's clear how a platform should be well structured systematically to avoid such kind of issues and that is why using a well trusted and accountable platform is way better than a cheap one with cheap fees.
We don't pray for a repeat of such awful incident anymore and that's why risk management practices of bankroll management and proper security technicality is needed always.

[HajiBagi]

But can we rule out the possibility that future hackers could pull off a massive bitcoin heist in the distant future??

We cannot actually write off such possibilities, but most exchanges have gotten wiser now, they leave only few BTC in their hot wallets and preserve a greater portion of the coins in their cold storage multi-signature wallets, so the possibility of such a heist is greatly reduced since social engineering only targets hot devices. Most exchanges learned from the mt. Gox experience and tightened their own security, although we still had recent hacks, but they're all tied to hot wallets and not cold wallets.

I agree with, no any exchanges will hear about the story of how that amount of bitcoin was stolen and still thinking of allowing many customers us save up to that in their wallet because if anything wrong happens and some was scammed with a big amount of bitcoin it is going to affect them, even though many people will not blame them much about it there are people who will still think that the exchange can not be trust and no matter how it is the news will go around and will make some people lose their hope in the exchange.

Another reason why i think that kind amount of bitcoin can not be steal by the hackers now is because every investors knows what they are doing and as a investor you should not keep all your bitcoins in one wallet, because no one can predict the future and scammers are very dangerous that you will not know when they get into your wallet, so i think it is also another reason why hackers can not steal that kind of bitcoin again.

[Stalker22]

But how could hackers steal that much bitcoin back then but not today like mt gox 2014?  Arent hackers employing better hacking techniques today than in 2014? 
~

What do you mean by better hacking techniques?  What do you imagine real world hacking actually looks like?

It is not like in the movies where someone hammers on a keyboard for 30 seconds to finally "break into" a computer system.  Hackers today do have more sophisticated tools, but 90% of the time, it is just someone hunting for an open window - a bug, an unpatched vulnerability, or a flaw in a piece of software that someone forgot to update.

And that is exactly why things are different now.  As time goes on, developers find those bugs and vulnerabilities, fix them, and push out updates.  The software we use today is fundamentally tougher, better engineered, and way more resilient than the code running a decade ago.