Whoops,forgot the "many".
For the former part,Platinum is renowned for actively withholding the series they worked on onto their site(which I believe was removed from ad revenue back then),only ever releasing it early when someone comes along to do the real uploading,Platinum will forever be known as the clowns who do this.
The latter has to do with the 7000+ titles that got struck with a copyright due to a Korean company starting a stink with three others,Mangadex own failing system failing the hardest,with
2112 identified bodies so far,any amount of trust in the Mangadex system is now long gone,more so with a clause when uploading a new chapter that explicitly mentions that a scanlator must have approval from the author/publisher.
This functionally means,unless they've changed it,that all older series where the title is out of print,the author/publisher ceases to exist on this mortal plane,the series is hardly known,and/or the author/publisher can't even be contacted makes prospects very low.
The only silver lining is that Pixiv and Twitter works are now more prelavent,since there's no real legal backing that can actually stop the translations of those.