"If you beat the closing line,you'll win long term."
So lets take a soccer match.The line opens at +120 and
closes at +110.
in the first 15 min there are no goals and the odds raise to +120.
The circumstances are different,but if I took these odds,
it'd be identical as betting the opener.In fact I'll bet on what the "wise guys",who beat the closing line,had already bet.
no good.
You're missing the fact that some % of the time those who bet before the game would have a goal scored in they're favor in the first 15minutes.
If the line you are trying to beat goes from +110 to +120 after 15 mins, taking it at +120 at that point is almost surely a losing proposition. After a scoreless 15 mins you would need to beat the +120 by at least the spread to begin to have a +EV.