The perceived competitiveness is from the center of the board score distribution, not the range. Radiology is the largest specialty that has a mean Step 1 >240 among matched applicants. As you point out, the match rate is high, so this high mean must be due to self-selection. People judged competitiveness not only by the match rate, but also the likelihood that they personally can match at the program they want. If you have a 235, you're below average and even though you will likely match, it is less likely to be at the program that you want than if the entire field of applicants were shifted to the level of internal medicine or pediatrics.