That's the reason I don't reject the idea out of hand. Add to that Beltre's demonstrated ability to have a monster year and it is appealing. But you can't pretend the guy has been anything resembling consistent.
Lowell doesn't walk much, but he hits for high enough average to maintain a tolerable OBP. The last time Beltre had an OBP as good as Lowell's career average was his amazing, mostrous, no-way-in-hell-he-does-it-again breakout season in 2004.
He did the same thing with the Dodgers, and Dodger Stadium is on the big side, but not exactly as big as Safeco National Park.
http://www.baseball-reference.com/players/split.cgi?n1=beltrad01&year=2002&t=b
http://www.baseball-reference.com/players/split.cgi?n1=beltrad01&year=2003&t=b
http://www.baseball-reference.com/players/split.cgi?n1=beltrad01&year=2004&t=b
As you can see, even in his breakout year, Beltre hit better on the road. I don't think you can blame all of that on playing 19 games at pre-humidor Coors Field either.
So this is hardly a phenomenon reserved to his Mariners days. the guy is apparently just a road warrior. And before you try that hard to put your interpretation on the numbers, and especially before you mock people about the numbers, you might try looking at ALL of them.
And take a look at his bb/k while you're at it. Rarely better than 1:3. The guy walks maybe 40 tiimes a season in a good year.