I would also say that, if an international prop is not struggling physically by minute 60, then they're not working hard enough and need to be hooked for that anyway - with the way the regulations are current written, it makes absolutely zero sense for a starting prop not to be looking to completely empty the tank by 50-60 minutes.
I would agree that the fashion needs a rethink, cause I don't care for it, but that'll only happen with the regulations changing. I would very much be in favour of only 5 substitutions being allowed, with injuries beyond that requiring to go down to 14/front row injuries requiring another player be subbed off.
Puja