Because each of those firms will generally have a few schools they recruit from. Odds of getting a job go way up if you head there. Also, MBA is no longer monolothic like it used to be, now you have Finance and HR MBAs. Some schools have better programs than others and may not be a top 25 MBA but are top in a niche area you may want to pursue.

Also, a lot will be determined by your GMAT score. I'd pay for a study course and do as many practice exams as you can. GMAT will open doors you didn't think possible if you do well.

One last thing. grad school Tuition costs are guaranteed, a better job is not and the risk is all on your shoulders. Check placement statistics of the school, but know they aren't audited by anyone and are sometimes not accurate. MBA is a fairly good bet, much better than most other grad programs, but grad school loans and their higher interest rates are no joke.