can a table saw with a parallel fence, cross cut fence and mitre gauge do all of the jobs a dual bevel mitre saw can
They're different tools that do different jobs. A table saw can cut the same range of angles that aa miter saw can, including compound angles, but trying to cut the end of an 8' or 10' piece of moulding is very awkward on a table saw using just a miter gauge. It's easier if your table saw is equipped with a sliding table, but still not as easy or as accurate as a miter saw in a station that provides plenty of support.
A second difference is that you can easily move a miter saw to where the work is, but table saws other than small "job site" saws are usually too big and heavy to take to the work.
If you're trying to decide between the two tools, or wondering whether you need both, think about the kind of work that you do. If you're cutting lots of long, narrow pieces, a miter saw would be a great tool. So if you plan to install a lot of moulding, lay a hardwood floor, or build a cedar strip canoe or kayak, you'll probably want a miter saw. A good policy is to buy a tool when you need it; for general woodworking, you might want to buy a table saw now, and buy a miter saw when the need arises.