They definitely were paying attention to the ratings.
That's why they brought in the Borg Barbie.
Back then I never considered not watching/enjoying a Star Trek series - it was completly incomprehensible.
Enterprise managed the unthinkable and weaned me off, (in fact I think it changed the whole addictive nature of TV for me, so in part I am greatful) but truth is I've never enjoyed Star Trek as much since it soured the milk.
But there was a time where I worried if they'd try a similar trick with Enterprise - like add a hot 18-25 year old blonde - and wondered how strong my resolve would be. Back then it would have been enough, probably.
Season 4 did push Voyager up a gear, as much as Worf did for DS9.