FWIW the Look Up feature, whilst built in to macOS, can also be implemented using "services" which are a way to plug in to other apps and system features like text rendering and highlighting. I can also select text in your message, right click, services -> "Add to music as spoken track". That's a plugin offered by an app. It's only one extra click.
My perspective on why OpenDoc/OLE failed are different to yours. The model in which apps host targeted plugins which don't affect data formats proved very successful, the model in which an app is nothing but plugins wasn't. And if you want to talk about marketing and culture, well, OpenDoc and OLE both benefited from corporate marketing. Using OLE was part of Microsoft's "Designed for Windows 95" programme, which came with a badge and marketing dollars attached. This concept was heavily pushed at the time. OLE had more success than OpenDoc but only temporarily and only because it was a less pure implementation of the concept, closer to fancy plugins than truly decomposing apps into components.
I think the reason they didn't take off was a mix of technological problems and user demand problems. It wasn't people/policy related. Quite the opposite: both technologies lived on long after the real problems had become apparent.
Programming for both OpenDoc and OLE was extraordinarily complicated. The developer experience was atrocious. Making your app OLE embeddable required mastering not only COM and Win32 programming but dozens of other poorly documented and flaky APIs, like for compound documents. Code generation was rampant, everything was memory unsafe. I never did OpenDoc apps but I heard it was a very similar experience.
Then there was the user experience: if you embedded an object from an app and sent the resulting document to someone else who didn't have the app, or had an old version of the app, then the document would just have a hole in it. Useless. OLE tried to do a kind of weird mind-meld between totally different app GUIs, meaning that depending on where you clicked in a document the hosting app could look totally different. There were dozens of problems like this.
In the end it was all rendered irrelevant by the web. On the web, if you share a document with someone it always appeared for them correctly (or if it doesn't, it's a minor and quickly fixable bug). Reliable sharing mattered more than anything else and so all the non-web platforms started dying out.