For most of manufacturer's plugins : YES !
When in doesn't work, it will cause Live to crash at startup during plugin scan, I usually give it a second try to confirm the behaviour and upon crashing again I know that I have to keep that plugin at the root of the VST folder like it was by default.
If you're using Waves Plugins, you have to keep the WavesShell-VST files at the VST root as well.
For other manufacturers it's a matter of trial & errors but again, the numbers of plugins that are causing Live to crash when placed in a subfolder is not that big, and I've seen this number reducing quite a lot with plugins & Live updates among time.
Once in a while ( because of plugin updates ) you'll have to maintain that files structure of course. When some manufacturers are already using that subfolder structure by default for installation, many still don't and therefore after updating, you'll have to manually move the new version from the VST root folder to the manufacturer's one you've created, therefore overwriting the older version.
Something else good to know is that depending of files permission, you'll be asked for your admin password under macOS in order to move some plugins, but not always. Just don't be surprised when it's happening.
Once you've updated & moved your new plugins version, Live will not always rescan them ( because that was done already with the previous version ), so it's a good habit to go to Live's Preferences and "File & Folder" Tab and to rescan your plugins to update Live's cache.
So it's a bit of work to maintain this structure, but as a result you'll have almost 100% of your plugins organised by manufacturer's name, like it behaves under Logic or in the AU plugins list in Live. You've got an exemple of the result in the following picture.
On Pic 3 you can see the plugins that had to be left in the VST root where on Pic 2 you can see the new behaviour in Live's VST List.