How?

In the 90's most software was closed source but cracks/trainer were always available.

Even for Rayman that had multiple (26?) cd-check during the game.

Security is mainly slowing the attacker because there's a maximum amount of stuff a human can do in 24hours. But now if you can simulate thousands of human attacking a system in different ways, it will crack.

Just like many stores have lock on their doors and, insurance if someone breaks the lock.

I'm guessing data security insurance will become a huge market in the years to come.

Aren't we in agreement then? Taking your lock analogy again, people don't put locks on their bikes because they protect them completely, but because they slow down someone who wants to steal them. Given enough resources everything will be cracked, it doesn't mean that making it harder is useless. People cracking games in the 90's may not have had the source code but they had the machine code and knew what to look for and where.