Prior to 1991, the Billboard album chart was compiled based on a point system. Billboard reps would call record stores around the country and ask them what the top sellers of the week were, and then assign points based on this data. It was obviously prone to a lot of errors, one of which being that the industry assumed albums were like singles: they started lower on the charts and built up to their peak positions over time. This influenced people's perceptions.
In the Summer of 1991, Soundscan was used for the first time in order to compile the Billboard 200. Immediately, it became apparent that albums sold a lot more out of the gate than previously believed. Soundscan also proved what potent sellers hip-hop and country truly were.
The likelihood is that True Blue and Rhythm Nation 1814 were the top sellers their respective debut weeks. But all the data we can go on is what happened post-Soundscan, since we don't really have accurate prior sales data. Madonna's first post-Soundscan album was Erotica, which sold 167k in its first week (though this album was released during a period of relative backlash for her; it's possible that both True Blue and Like A Prayer sold more in their first weeks). janet. held the record for best female opening week for five years. In 1998, it was broken three times: first by Ray of Light, then The Miseducation of Lauryn Hill, then Supposed Former Infatuation Junkie.
I'm not sure where you found the number of 210k for Whitney's opening week in 1987, because week-to-week sales weren't really tracked that well if at all, but honestly that sounds like a decent idea of what it would have sold out of the gate. Bad did debut at #1, however. I think Thriller may have debuted at #10.