I feel the same way... I don't think it is possible to get new legendary girls without spending kobans now. For all other legendary girls, I was able to get them on the last day or within last day, just by playing all the time and spending all combat point that regenerated.

Now, after 1 day of event, I am at 15/100 attraction. With this rate, I will be done in 6 days... 2 days after event ends.

p.s. RNG be RNG, your mileage may vary, and you could be having a better luck.