The great thing about the amigas custom chipset was/is that it gave each model a long life, 24 years and counting, whilst PCs are obsolete in 4years or less.
If a future amiga used off the shelf parts, it would need to be regularly upgraded too, GPU's have a life span of just 2 years or so, and newer software would not run fast enough on a 4 year old amiga that used off the shelf parts.
Fast processors and gigabytes of ram encourages lazy programming.