Alonso's recent Aston Martin contract extension means he will carry on racing until at least the end of the 2026 F1 campaign, by which time he will be 45.
That would make him the oldest F1 driver to compete since Graham Hill in 1975.
Alonso already holds the record for the most grand prix races ever started and is set to hit an unprecedented 400 GPs at the 2024 Qatar round.
It is 23 years since the Spaniard made his F1 debut, next year will be the 20th anniversary of his first world championship, while his most recent world title came for Toyota in the 2018-2019 World Endurance Championship.
McLaren driver Norris was asked about Alonso's longevity in the Chinese GP. While also answering a question about whether he would like to race for so long, Norris replied: "I'd better be careful what I say. I think it takes a lot of dedication – I don't think anyone thinks Fernando lacks that in any way.
"He shows that with everything that he does in life. Whether it's at the track or away from the track, in different sports or whatever.
"So, it depends on what you want to do. Everyone is different. It's rare that you see someone commit for so long in any sport.
"He's probably one of the oldest guys competing at the top of any sport in the world and I think to be able to do that at the level that he has done and continues to do, you're probably never going to potentially see it again, within Formula 1.
"And if you do, it's going be extremely rare. [I have] a lot of lot of respect for that kind of thing. I have no idea if I'll want to do it in 20 years' time, if I'm still going strong.
"But I love where I am now and if I continue to do such a thing, yeah, we'll see."
Speaking alongside Norris, Ferrari driver Charles Leclerc and Alpine's Esteban Ocon were equally uncertain on how long they envision their F1 stints ideally lasting.
Ocon said Alonso's record is "a dream career for any athlete or racing driver" and added, "I don't know if I would still be racing at his age but, truly, his dedication is something that is an example for all of us".
Leclerc said it is "difficult to imagine myself in 15- or 18-years' time still [racing] in F1", but also revealed he is eyeing a specific new late-career challenge in any case.
"I would love to be racing still for many years," he added. "I would like to experience other things like Le Mans – that's definitely a place where I will see myself racing one day.
"I mean as long as I am fully motivated then I will race. And I love what I do, so for now that's what I want to do for the longest time possible."
