The act of re-issuing the shares would have the opposite effect on supply, causing the price to go back down. You can't create profits by retiring and then reissuing shares.
We aren't talking about re-issuing shares--we're talking about buying them back to be re-issued at a later date. The act of buying them back would shrink the supply and (in theory) drive up the price.
Presumably, the stock would be reissued at a point where forces other than supply & demand would have had an impact on the price as well. Yes, the additional available shares on the market would cause a dip--but that dip would not necessarily negate the other effects that (could have) impacted the stock price since the buy-back.
I'm not ignoring the effect; I'm just not viewing it in vacuum.