The only surprising part is people earning a living from a trade/profession that cannot do parts of that trade that they require to be competent at it, I know a good few people who i consider excellent drivers but have not one clue as to what goes on in the mechanical parts of the vehicle, the same applies to me with computers ,,but I`m not making a living from it, working with & on something[chainsaw. logging equipment etc. should give some idea as to being able to carry out routine repairs/ maintenance, to be able to do the job properly [ but in this day & age a lot of folk it`s to much hassle, pay some one else to do it] so slowly the skills die away to repair, & we have become a throw away society, + the fact a lot of today`s kit is easier to replace than repair, or you need VERY expensive diagnostic/special repair kit, so the circle becomes ever more tight