Uplinker,
The rhs tiller is a cost option. It's not specified because it's not necessary and in the current era of low-cost aviation anything unnecessary is ommitted.
Taxi training cannot be done in the sim, so the only option is to do it on the line in some form of formal rostered training. As it's not essential and training requires resources, it won't be done.
Taxying a large aircraft with 200 souls on board around a complicated airport, at night, in rain or low visbility is not comparable with driving a little 2m wide car on public roads.
Following on from the above, your fury at the attitude of those who understand an airline's policy of only allowing the PIC to taxi the aircraft is interesting.
Personally, I fully understand it, and although I know there are many low hour FOs who would do a great job, I also know from experience that there are a fair few who would not be up to the task - and I personally wouldn't want to risk my livelihood to massage their egos.