It almost seems to me the cabin crew did not do their job prior to departure. Most of the flights I have been on have the kits distributed already before I board the flight. If the cabin crew at least did their checking before departure, they could have realized it and asked to have them brought onboard when you were still at SFO.

A few years ago, I was on a SFO-NRT flight. There were no slippers. The 744 UD FAs basically threw their hands even with multiple passengers asked for them. Some people on FT thought we were just being picky business travellers. People who understand the Japanese culture know that serving up the slippers is part of the hospitality and it was pretty bad to not have them at the gate and doing nothing about it. Anyway, it all ended up well as the LD FAs actually requested them from Ground Services.

It is similar here. Not having it not only brings inconvenience but also shows the attitude and preparedness of the cabin crew.