Companies want to have low turnover rate. Companies do not want sensitive or confidential information going to a competitor. Companies do not want skilled professionals going to competitors. Aside from money, your original reasons for leaving your job will still be present after accepting a counter offer. The money extended to you in the counter offer often comes out of your next raise or bonus.
Companies usually have strict guidelines about salary increases and promotions.
When promotion time comes around, managers remember who was loyal and who was not. If the company hits rough waters, you will be the first to be let go. You had to threaten to leave in order to receive the rewards and career path you have earned. Often, when you accept a counter offer, your manager will already be looking for your replacement. In our humble opinion.