Three websites using the same domain - one is possibly hurting other two

[notNewB]

I was asked to take a look and make a suggestion on a website. The owner has 3 projects, and all 3 use the same domain - domain.com/content, domain.com/archive, domain.com/shop

The news website is the one I'm working on - it publishes news, informational articles, and interviews.

The archive is an archive where they published 12K photographs taken during WW1. Each image is uploaded to a separate page, and those pages are not SEO optimized. In fact, tens, twenties of such pages use identical H1 titles and those pages differ only by a digit in their URL. Like "domain.com/archive/dying-soldier-1101" and "domain.com/archive/dying-soldier-1102". 10K of these pages have not been indexed.

The shop is a place where they sell merch.

Everything went live 5 months ago.

My question is - does it make sense to convince the owner to transfer each project to a separate domain name? He wants to do this, but not right now, like after a year or so when each properly gets big enough. I've read that bad quality pages affect the overall SEO health of the website, and I'm worried that the bad pages the archive has (Archive essentially doesn't care about SEO) are affecting (or will affect) the News website.

 

[roydan]

He wants to do this, but not right now, like after a year or so when each properly gets big enough.

IMO you should just explain that this would be a lot less complicated to do now, and he'll benefit from it for longer because it won't slow his success.
I don't really think they hurt each other, but they'll most likely confuse some people. What ranks first when people are searching for the domain name?

 

[notNewB]

What ranks first when people are searching for the domain name?

If you search the domain name, the news site is ranking first because the homepage (domain.com) is 307 redirected to the news landing (domain.com/news). There are 3 big buttons in the header to switch between landings, something like:

this would be a lot less complicated to do now, and he'll benefit from it for longer because it won't slow his success.
I don't really think they hurt each other, but they'll most likely confuse some people.

This makes sense.