Bob,
You are right as far as my understanding is current.
You got Studio Artist whatever that has a neat inner core of effects, but the carrot in front of the nose is, upgrade and you can use third party vst's, which they have locked you out of until you fire up the plastic card.
All honesty, upgrade or purchase of Studio One 3 is entirely worth the expense. These are the first guys to incorporate a fully modular synth and/or audio routing matrix native into the program. Reaper, Sonar cannot touch this function without relying on external programs to fill the shortfall that they cannot handle.
Richard wisely advised to look at Studio One. More hardcore critical if you are a keyboard player. Sonar takes care of us state of the art, nothing else needed if you are a guitar banger or requiring support from an audio source.
Love to all,
John