the role of a DAW is to allow us, the user, aka the paying customer, to use the synths, tools and plug-ins that WE choose, it is not the role of a DAW vendor to control what plugins we may be allowed to use.
It matters not who is right/wrong on the technical level.. i do not know, and i do not care one bit if VST2.4 can do everything that VST3 can when i am looking at a piece of software for a $2200 synth that only runs as VST3, or similarly, other users that cannot fully exploit a $1000 VST package without VST3 support.
as more companies support VST3 the cheaper option for many users will be to switch DAW, or at least not upgrade, and Cakewalk needs to mark their timing of VST3 support very carefully.