I really enjoyed Voyager even though you may see a lot of my anti-ranting on this site.
So I think it's already been established that some fans might like only Seasons 1-3. If you like season 4, you might as well stick around until the end. What happened in season 6 that would have alienated the fans?
But to actually manufacture a 1-5 set and sell it for more than a complete series? What's the point of it other than to admit that 6 & 7 got derailed?