Oh dear
You do realize I was talking about block generation!
How about something easier for you to understand.
Say someone invents a new super ASIC that's thousands of times faster then the best ones currently on offer. They set up a farm, grab 99% of the net hash rate, attack the block chain a bit, let the difficulty rise to a hundred times higher than it was, then switch the farm off. Bitcoin is stuck at a crazy high diff and effectively ruined, transactions grind to a halt, game over.
Or someone with a lot of money can amass a huge ASIC farm and 51% BTC.
For sure, a disruption of the BTC network can come in a number of ways, a smart investors doesn't keep all their eggs in one basket, be it BTC, alt-coins, fiat, gold, stocks, houses etc.
That's why I'm glad there are altcoins in crypto. If something happens to BTC, I'm done.
Altcoins let investors hedge their funds.
Imagine Nasdaq only had one kind of stock on there. Who would invest in that?