That is what I am concerned about. However, being disconnected from Internet or electricity for even hours won't get you fined. But Vitalik had mentioned around 75% uptime (It was even less than that, I don't remember correctly) is fine as well. It is not that you won't be affected. Yes, you will be but it will still remain profitable.
Could you give me a link to similar words of Buterin. I didn't hear about the fact that node owners will be allowed to stay idle for 1/4 of the time. Previously, the developers focused on the fact that the nodes should work smoothly. Perhaps now, due to the large number of nodes, they decided to reduce the requirements for the time of operation of the node.