I think its because they were getting fewer and fewer buyers, so they went for what the younger people were interested in which was tuning which then after NFSU became a huge hit, then tuning grew, and now its grown to where whoever owns that section of EA is trying to merge the exotics with the tuners hoping everyone would get along, but that isn't so.
Its common for EA to do that so its no big surprise. They are serious when it comes to trends, if the trend is out, they leave it in the dust and shun it.
And yes, for those that don't believe in it, it is possible to tune exotic cars with parts. Also, no it was never possible to beat a porsche or a high end car with a punto.