I think it isn't much overrated. I have to admit that Reagan did extremely well (the 2020 Democrat should perform like this). I always felt that his closing statement ("are you better off than you were four years ago?") has the final nail in Carter's reelection coffin. Even if I didn't know the outcome, I would have said "that's it, Carter is done."
Reagan was much weaker in his 1984 debates, probably due to early stages of Alzheimer.
Reagan won that debate hands down but still it didn’t feel like a rout that Bush-Kerry first debate and Obama-Romney first debates were . In Those debates There didn’t seem like a single point where Bush and Obama won an exchange and half way in it felt like both of them just gave up . Carter I beleive got Reagan on one exchange when he pointed our the real Reagan signed tax increases into law as Governor .
What that debate did was ease some doubts that people had about Reagan being a warmonger type cowboy and once that happened Carter was done as that was all he really had left by that stage .
Yah your right Reagan himself said the are you better of than you were 4 years ago was his best line of the debate not the there you again like like people think .
On the 1984 debates I think it was cause it’s much harder to debate when your the incumbent then challenger since you have to be more on the defensive while as challenger you don’t need to do that . The same thing happened to Carter , Bush , and Obama where they all lost the set of debates when they were the incumbents and even Clinton debate performance was worse in 96 than in 92