The short simple answer is simply hotels are charging what people will pay. The OP believes what the general hotel using clientele is willing to pay is too much...
In the last year I've stayed in nice, name brand hotels (typically Marriott family, Hilton Family, or IHG Family) for under $100 several times. I've paid over $300 in another case... (For that matter I paid over $400 for the smallest Hampton Inn room I've ever stayed in, but that was the going rate for the market and time of year).
Dates matter. Location Matters. And what is driving the price may be completely unknown to to you, but certainly reflects the demand of whatever event it is.
As an example, I'm currently booking rooms for Volleyball tournaments for one of my kids... We are paying a "reasonable rate" of around $150 a night. Same hotel class and location open booking is north of $400 - because this tournament is bringing in literally hundreds of teams from out of state...
Same deal for a hockey tournament another kid is playing in... We pay a reasonable group rate. Open rack rate is north of $300. In Minnesota. In the Winter. In a non-descript anywhere type of town.