Shuey never had a teammate finish top 2 in the driver’s standings. Hamilton’s teammate beat him to the title. Different levels to this.
It’s easier to win titles when your car is so much better than the opposition.
Michael was always the contracted no1 driver in the garage particularily at Benetton and Ferrari. His team mate in the championship years at Ferrari was Ruben Barrichello. At Benetton in 94 and 95 his team mates were a mix of JJ Letho, Jos Verstappen and Johnie Herbert.
Ruben was handy, Jos was occasionally quick and Herbert was average and all of them No 2 drivers.
The Benetton years were shrouded in cheating allegations of traction control and the Ferrari dynasty was built on the single biggest money splurge by a team in F1 history.
Lewis had Heikki Kovalainen in his sole Mclaren championship and then Rosberg/Bottas for the next 6. Rosberg alone was way better than any of Schueys team mates and Bottas has had his moments. But, just like Ferrari Mercedes has the best car but they are a bit smarter having a very fast team mate as well.
The only way you could ever get a true drivers championship is to put all 20 drivers into the same spec Mercedes/Ferrari or Redbull and let them loose.