Hindsight is a dangerous thing
It's unfair to judge the programs of yesterday by the standards of today.
In 1995 we looked at Excel for Windows and looked back at 1-2-3 and shuddered: who would use such a thing? Who would pick "/" as the menu key? Same thing.
Notes was immensely ambitious and powerful for its time, and allowed you to do things that no other system could do. Circa-1999 Exchange Server could barely stay up, let alone provide a basis for complex workflows and custom apps.
Today Notes needs to be quietly put down, but you can't blame it for being bad back in the day. The interface was not great - you might even say poor - but the alternatives from that era were not exactly fabulous either.
If you want a prediction, in 2040 the Reg readers will be pointing at our Metro/Material Design UIs, and our unsecured cloud assets and scoffing "what were those jokers thinking?!" But we do our best today.