The official Pi 4 (and recommended) power supply is 15.3W (3A at 5.1V). I assume this was selected in order to satisfy the power requirements of the Pi 4 running at full capacity.Maybe we should consider the "defect" to be a "feature", as I'd suspect the 100 watts that USB Power Delivery could push could be dangerous?
If you were to attach a 100W supply (assuming the board was fixed to properly recognize it), I highly doubt it would try to draw more than 15.3W. I've never heard of a power supply trying to "push" more power than the device is trying to draw. I don't even know if that makes sense, electrically.