This point is also something many people who push the argument that drafting Love was a wasted pick because he sat for a few seasons and the Packers couldn't take advantage of contending with a quarterback on a rookie contract before having to back the Brinks truck up again don't fully account for. They also choose to omit the fact that the first 2 seasons Love sat, the Packers' quarterback won league MVP (and year 1 there was a solid chance there wouldn't have even been a 2020 football season at the time of the draft due to COVID)...so a developmental qb prospect like Love wasn't the worst idea in the world at the time.
Besides Russel Wilson (3rd round pick, inserted to a team built on running the ball with a historically great defense) and Purdy (Mr Irrelevant, playing with a roster full of HOFers on both sides of the ball who are now all collectively getting long in the tooth/expensive just as the 49ers have to decide whether or not to pay a 7th rounder $50M a season), what other franchise that have found themselves in or winning a Super Bowl have done so with multiple years of a quarterback on his rookie deal? The Bengals got there early in Burrow's career (#1 overall pick), then instantly had to extend him to a huge contract and have scuffled through the last two years watching him get beat up/injured. Trevor Lawrence won one playoff game and is now playing on an extended contract. Mahomes is the exception to every rule right now (like Brady was a generation ago), but he sat a year and the roster he walked into won 10 games the season before with Alex Smith as their qb. And Mahomes was extended rapidly, too.
More often than not, a top 5 qb winds up on a bad roster to start with, and by the time that team is ready to contend on an annual basis he's already getting a huge extension. And if that top 5 qb isn't good enough to rapidly turn a franchise around regardless of the rest of their roster, he becomes an NFL journeyman before his rookie deal even ends.