The story I heard was that Dumont himself said that his company would always be the leader in oscilloscpes, somewhat akin to the president of Ford saying the Japanese could never erase the 20 year lead that Ford had.
Mr. Dumont didn't face reality.  Then we see that his company made a Tek clone.  I recall LaVoie for one doing that.  Or was that LeCroy?  Then Fairchild did it but they were the same as Dumont I think.  I owned one and it was a good performer.
This corporate ball of snakes really puts so many at a disadvantage.  Greed certainly turns out to be an enemy, but it's human nature apparently.