I'd agree, I guess, on the home runs if he wasn't a .323 career hitter and still hitting .320+ and putting up 45+ XBH a year.
RBIs...where to start, probably his 2009 MVP season when he hit .365 with 28 home runs while making about 10 million bucks. He made less than Justin Morneau and Joe Nathan. Mauer ended the year with 96 RBIs.
The Twins appear ready to fly with $100 million-ish payrolls. They've got $80+ million to put guys around Mauer.
That's enough cash to NOT pump out a roster where Mauer is the only guy hitting better than about .255.