There were 13 quarterbacks drafted in the 2020 NFL Draft. One of them, Jalen Hurts, has already signed a massive extension with the team that drafted him in the second round. A pair of first round quarterbacks, Joe Burrow and Justin Herbert, are guaranteed to get similar deals soon. One or both may have them by the time you read this. The Dolphins picked up the 5th year option on Tua Tagovailoa's rookie contract months in advance of the May 2nd deadline. If Tua takes another step forward in 2023 he will likely sign a contract that will keep him in Miami for years. If it seems like an anomaly that four quarterbacks from the same draft class would get massive extensions with the teams that drafted them, that's because it is one.
In the 10 drafts preceding the 2022 Draft, there were 118 QBs drafted. 30 of those QBs were first round picks. If we expand the pool to QBs picked within the top two rounds, that number grows to 40. On average, there are 11.8 QBs drafted per year, with 3.0 per year being first round picks and 4.0 being selected within the first two rounds. Among those 118 QBs, 16 signed multi-year contract extensions with the teams that drafted them.
13.56% of the QBs drafted in any round between 2010-2019 signed extensions. When a QB is drafted, there's about a 1/7 chance that he will eventually go on to sign an extension. The odds that 4 QBs from the same draft class are roughly 2.3%. The schedule below lists information on QBs drafted in that time frame. In the "notes" column I have listed all of the QBs that signed multiyear extensions (I also listed Lamar Jackson as he will likely be extended by the start of next season.
The 2020 QB class has a chance to go down in history if Burrow, Tua, Herbert, and Hurts all sign extensions. It is an anomaly for that much NFL talent to be drafted in the same year. People hold the 1983 Draft in rare air. The 2018 Draft has already produced one MVP QB (Lamar Jackson) and has a chance to produce another (Josh Allen). If the 2020 Draft QB class stays true to the course it has already set, it will be talked about in the same regard as other historic drafts.