bonzobanana
Guru
All frames made in China but while Merida, Canyon and Cube are outsourced to 3rd parties, Giant at least has the decency to have their own factory - out of the four they're also the best for making bottom brackets that are actually round.
Merida is a big manufacturer probably second only to Giant in reputation for quality, they are a big OEM supplier to many brands although nowadays only the higher up models as Merida aren't as competitive in price as they used to be. Top end Specialized's would be typically Merida as they are linked financially. I think Merida bailed out Specialized and got some shares in the process but not sure how much of Specialized they own nowadays. Canyon were using Quest Composites for their carbon fibre frames and forks a while back but not sure if they still do as do Trek. They are a poor factory in my opinion with poor working conditions as well as inconsistent quality. Giant used to make some of the Canyon aluminium models but not sure if they still do. Cube are fairly low quality in my opinion using lower end Bangladesh factories typically. I think from a quality of frame and forks viewpoint then Giant and Merida are at the top.
https://www.thedailystar.net/business/news/germanys-cube-teams-meghna-make-high-end-bicycles-1632277
Really though as consumers we never know what factory-less brands are up to. They will keep moving to different factories to save money and those factories can vary in quality that is why there is more consistency to brands like Giant and Merida. For all I know Cube could have some of their higher end models made by Giant or Merida, its very difficult to know which is why I prefer to use actual manufacturers rather than glorified importers unless its a killer deal for the spec maybe an end of season large discount.
The big manufacturer behind many bikes we see especially aluminium is fuji-ta, the world's biggest manufacturer by far they make bikes for a huge number of brands. Probably middle ranking quality. In the EU we mainly get bikes from their Cambodian and Vietnamise factories nowadays because of EU tariffs applied to bikes from mainland China. Anyway they are the real manufacturer behind many western brands that many consumers focus on. Another big player is Insera Sena in Indonesia. There are maybe 5 huge international manufacturers who dominate a large chunk of the world bike market but then you have the importer brands that resell these bikes under their own brands.
You only have to watch Hambini or Luescher Technik videos to see how western brands cheap out on factories with some very expensive bikes made to appalling tolerances.
View: https://www.youtube.com/watch?v=LWhsXSa_csk