Well, one pays much more for what they get in a car (or a house) now than they did in the '80s or '90s. Expecting entry fees to remain static for years and years is unrealistic, given current economic trends. There are several factors that influence entry fees — though they make up a minor fraction of the race's budget – sponsors no doubt cover a good chunk of the budget – race directors naturally will want to maximize the income derived from them. Given a race size limit, if charging $75 for a theoretical marathon results in a full field of entries two months before the start of the race, event management may be encouraged by this fact to take the entry fee up to $80 or $85 (if not higher) the next year to get the extra money that a full field at that per entry level would provide to invest in things (transportation, refreshments, entertainment, swag, awards) that would help make their event an attractive draw when going up against similar events in the region and across the nation. It does seem rather sickening that marathons are approaching the $100 mark, even for non-gargantuan local ones — a nice local one in my area on a fast course had been around $60/$70 (late) through this year; next year's will cost $80/$100 (late) to get into. It is one that I had hoped to run this year, until a non-running injury derailed those plans, and would have liked to have run next year, but unless I can get a comp'ed entry (or contradict my own beliefs and bandit) it is likely that I will not ever run it. Incidentally, there are, however, an accompanying 15-mile “mini-marathon” ($50/$65) and a 10K ($25/$35) that I might consider running. I do suspect that the significant jump in marathon fee carries the intention to not only increase (or at least maintain) entry fee income but also serve to limit marathon field size.