My MacBook most certainly does drive three displays. My Mac Pro drives four, is quad-core with 16 GB RAM, and is almost five years old. I bet one a couple years old, like mine, could be bought for a couple hundred bucks.
I used Linux exclusively for fifteen years. I contributed to the kernel. When the boss put me on a Mac, I was surprised to discover how familiar it felt. I can use it just like Linux, with exactly the same workflow. The main difference is the cost of a Mac buys you nice hardware that "just works", and works very well. Mac has of course always been THE system for graphic design and publishing, so the display system is well done.