This is absolute horse shit and revisionist history. The majority of critics were positive or praised Empire when it came out. I have no idea where this narrative started from that Empire got mixed reviews when it released. The few major publications that panned it (like the New York Times) were in the minority.
Here's a sample of review quotes from 1980.
The Phantom Menace had mixed/negative reviews right out the gate.
Who cares?
This was my point:
Latching onto the least important part of what I was saying and missing my point.
Whether ESB started out as good, mixed or bad doesn't matter.
The point is that society's view on things almost always moves on. Things become dated.
There are very few timeless things in the world.
And movies age much faster than books.