Firstly I dont think the players having to walk 72 holes in 4 days has any impact on their play.
Walking 72 holes is not that tiring for anyone who is reasonably fit.
To me its not an unfair advantage to let someone who is unable to walk play in a cart.
The big thing is that they have people to carry the bags for them.
Right now they are taking 5 hours to play 18 holes, its crazy.
They need to start penalizing them shots for taking too long.

Someone give me a good reason why they shouldnt be able to take a cart/buggy if they want to and I will listen.