Does this mean that you can download and run OpenVMS, but after a year your VM will stop working and you'll have to download a new one and set it up all over again?
That, plus the fact that they're distributing it as pre-installed images rather than install media, tells me that they're worried people are getting too much value out of the free version, so they want to make sure it's sufficiently crippled that you could never build anything stable or useful on it.
VMS: the rock-solid operating system that'll never crash or go down, at least not until your 1 year license is up and you have to transfer everything to a new VM.