First off, your timing is off - no one in the 80's was talking much about a lot of new 100 seat aircraft.
Second, it has nothing to do with a DC-9 or 737 curse - just sheer number of airframes built.
With so many 737-200's available for a relative song (almost every LCC started with the -200) there hasn't been much that could compete with it acquisition-wise.
Of the current aircraft available now, only the 717 really fits the bill as a true 100 seater. The reasons why it hasn't sold has been discussed repeatedly in this forum so there is no need to go into that subject. The A318 is too heavy to be a cost efficient 100 seater, as is the 737-600.
Re. past aircraft, Fokker was always on shakey economic grounds, as was the AVRO RJ
. BAe was trying to get rid of it any way they could, even trying to sell it to a Malaysian company.
BBD and EMB were only RJ
manufacturers and, in the 1980's, Scope Clauses precluded dreaming of making a 100 seat jet back then.
Anyhow, BBD delivered their first 70 seat jet only 2 years ago. and the first CRJ-900 delivery was only this January - but the CRJ-900 is not even close to being a 100 seat aricraft. Standard one class configuration is 86 seats (I believe that the 90 seater is with a 30" pitch, reduced rear baggage hold, no galleys and one lav...)
The E190/195 haven't even flown yet (Sept. 29 was the first 190 fuse join.) However, they do already have 125 firm orders and options for another 100 aircraft.
I believe that: as the travel industry continues to recover; together with the eventual Star Alliance order; and with the continued loosening of Scope Clauses, I am quite confident that you will start to see a good number of 100 seat aircraft ordered.
Nationalism is an infantile disease. It is the measles of mankind. - A. Einstein