It seems like USB A/C are going to be that. You can already buy outlets that have both mains and USB ports, there are even dual USB C outlets now, that can do 30 watts:
What actually worries me about this is that they are all backed by tiny switch mode power supplies, and if not designed and built correctly they have a habit of exploding. So now your hotel has hundreds of potentially explody boxes hidden in the walls.
Both USB-A and USB-C chargers require active logic. USB-C is more complicated because includes both USB-C and legacy USB logic. USB-PD is the most complexity.
When current manufacturers claim USB-PD they mean PD 2.0 which requires the CC line (Only included in usb-c to usb-c) to signal and set the voltage. When PD 3.0 is included, they usually call it quickcharge 4.0 or PPS.
Otherwise every single cable would have to be built to handle the highest possible power delivery rate (100W for USB-C).
I'd be impressed if you could cause a short on purpose with significant force let alone fumbling in the dark.
It's really easy to buy some substandard USB-C cable that lies about it's capability.
Depending on what standards your existing ports support and what power input the iDevice can accept, you may find that a simple A->C adaptor will suffice. You may not get the fastest charge possible so in that case will want to move over sooner rather than later, but this may be an inexpensive (in terms of money and effort) stop-gap measure.
Also, fast charging your battery more often could be better since you're not fully discharging and recharging your battery.