Isaac Newton once said that he was able to accomplish so much because he was "standing on the shoulders of giants," referring to the accomplishments of those before. This is the same situation. Michaels and Madden pioneered their field, and I'm sure Collinsworth has been able to learn from their careers and thus develop his own broadcast skills.
Of course, Madden and Michaels pioneered the informal broadcasting method of chatting during the game on Monday Night Football. Of course, this style of commentary has been commonplace for decades in Baseball booths. But, yes, Collinsworth - in addition to most other football casters - should credit Madden and Michaels for bringing this type of commentary to football.
Yes, I do think that they started a huge trend, and that the other people who start working on these discussions do owe a lot of thanks to these men who pioneered the whole idea. I think that now there are actually to many of these out there on tv.
Nope, but I do think that he owes at least a nominal debt of gratitude to John Madden and Al Michaels for the work they've done. But broadcast banter and discussion existed in broadcast sports, particularly the NFL, long before those two rose to the top. I'm sure Howard Cosell would have an issue with calling Madden and Michaels banter pioneers.
I do not believe Cris Collinsworth owes a large debt of gratitude to John Madden and Al Michaels for pioneering NFL broadcast banter and discussion. I believe these things would be popular without these two's input, so Collinsworth could have easily followed someone else entirely. Collinsworth is his own person, he shouldn't have to be thankful to his predecessors just because they came first.