Just because the ratio of applicants to place doesn't seem particularly high doesn't mean that it isn't extremely competitive still.
You have to bear in mind that because banking has the reputation of being competitive, most of the poor/average applicants are likely to be put off. That means that whilst 10 of every 50 may well be useless, the remaining 30/40 are motivated, attend a top university and achieve good grades, understand the industry and have a whole host of ECs. If you're competing against 30/40 individuals who could all arguably be regarded as good enough, it's tough.
I'd argue that because the standard of applicants is generally higher it can actually be more competitive than industries which have a higher applicant to place ratio. For example, pretty sure I read that Vodafone (or some other big corporate) had the 'most competitive' grad scheme as it had the most applicants to places. Yet, the reason behind the absurd number of applicants was that their grad scheme was the first search result when you searched 'graduate scheme'. How many of those applicants really wanted to work for company XYZ and had the required skills? My personal feelings are that the number is less than for banking.