When you see interviewers and album reviewers and other talking heads pushing these comps it’s not because Billy Bush or Ryan Seacrest or Carson Daily are all coming up with these comparisons on their own. His PR is pushing the narrative in this direction and from a PR standpoint who wouldn’t want those comparisons. The problem comes when, as of right now; after releasing multiple albums, I am still waiting for the music to match hype.
Another comp career wise would be Justin Timberlake, he did the boyband to solo superstar jump and his PR team boldly implied that JT was the heir apparent to Michael Jackson’s king of Pop crown. The thing is, Timberlake came out of the gate smoking with banger single after banger single. So while the suggestions were weighty they at least made sense.
I think it may be worth separating the Elton and Bowie comparisons if that's the barometer. I'm not gonna claim I've been stalking Harry Styles media but, honestly, all I've seen on Elton v. Harry outside of here is like...the Halloween costume, general fashion choices, and Elton saying Harry's House was one of his favorites of the year. Outside of being British and loud in clothing I just don't see the comps that much between them as musicians and I don't think it's being invited tbh.
Bowie/Styles is definitely more common but I just have a ton of trouble dinging a guy's music for what may or may not be a marketing campaign by people poised to make money off of him and, honestly, I again see it more as a comparison of style and presentation as opposed to music. I don't think it's the most insane comparison career wise - both spent the first half decade or so of their career in creatively derivative bands/groups where they likely didn't get to flex their talent to then break off solo and really do what they want. Both are unapologetically "out there" personality and image wise with little regard to what the population at large expects*. To your point on Elton and Bowie, the big issue with the comp is that Harry hasn't, in my view, had that Magnum Opus. Now, I'd say Bowie hadn't either yet (like Elton), - like I'm trying to consider that Bowie really didn't take off in his time until his fourth and fifth albums which then had people go back to The Man Who Sold The World for instance.
On the larger scale, I just don't have it in me to really give the comparisons much mental weight for, well, the Timberlake of it all. To your point, the Justin Timberlake comparison seems instructive. JT, I'd agree, aggressively pursued exactly what you might expect him to if he's going the Jackson route - he flamed out hard after 20/20 Part 1 (and even 20/20 Part 1 started to show signs). A lot of the Styles narrative will probably be what his Albums 4-7 look like: is it more Honky Chateau and Hunky Dory or more Man In The Woods? Time will tell.*
* I do think we disagree on the level of bangerness on JT vs. Styles singles (a lot of JT's stuff really hasn't aged well to me), but I also think the pop environment of 2002 is so different than the one of 2022 that it's hard to really compare them. There's a reason a ton of folks thought Zayn and Niall and not Harry would be the breakout of OneDirection after all - because they would be in 2002.
