I realize this sounds a bit cliché but... At no time watching either Baines or Smith did I ever think "That guy's a HoFer." No sir.
One of these is not like the other, though. You can make a pretty solid argument that Lee Smith is a top-10 relief pitcher. (He's #5 in fWAR, for instance.) How being a top-10 relief pitcher stacks up in the grand scheme of baseball achievement is another question, of course, but still.
The only thing Harold Baines was one of the best at is longevity (#20 all-time in games played). In Bill James' taxonomy, he's a Definition-D HoFer, at best:
Definition D: A Hall of Famer is a player who rises well above the level of the average player, a player who would be capable of contributing to a pennant-winning team, and would be one of the outstanding players on an average team.
One thing I think we can safely conclude: Harold Baines must be a hell of a nice guy.
EDIT: To expand on this, here are some players who were Baines' contemporaries (1980-2001) and are not in the Hall despite having more rWAR than his 39.9. I'm leaving off the obvious steroid red-flaggers and people still on the ballot:
Albert Belle, Jack Clark, Julio Franco, Andy Van Slyke, Gary Gaetti, Darryl Strawberry, Don Mattingly, Ellis Burks, Keith Hernandez, Lenny Dykstra, John Olerud, Dwight Evans....
There are a bunch more names, but I had to stop there for a moment. Dwight Evans has more rWAR than Harold Baines during Baines' playing years,
even though the first eight years of Evans' career fell outside that period. Yet Baines is in and Evans is not.
....Mark Grace, Chuck Knoblauch, Matt Williams, Willie Randolph, Tony Fernandez, Devon White, Dale Murphy, Robin Ventura, Brett Butler, Tony Phillips, Kenny Lofton, Will Clark, Lou Whitaker.....
Now of course WAR is not and should not be the ultimate arbiter of these things, but it seems like a particularly valid yardstick in this instance because Baines played for so long. A guy who played for 22 years without producing more value than Andy Van Slyke did in 13 is not a Hall of Famer. It really is that simple.