Think footrests need to be chemically stripped before you polish them as they are coated in a protective paint, not tried it but Nitromors (something like that anyway) might be what you need to use first
I polished the pipes on my SS to mirror finish ( well nearly). I used various wire brushes on an electric drill to start with. This stripped off all the brown discolouration. I also used a few flap wheels to help remove the pitting and smooth out the original finish which isn't particularly smooth. I followed this with emery cloth in a medium grade then #150 wet & dry, #400 wet & dry and finally Solvol Autosol chrome polish and lots of elbow grease. After a week or so of use the pipes will start to take on a bronze hue again. This is where the Wonder Wheels comes in. Applied once a week when you wash the bike will keep them looking silvery.
As for the footrest hangers. These are anodized and to polish them you will need to remove the anodizing first. Easiest way is to spray them with oven cleaner and leave them for a few hours. Naval jelly type rust remover will also do it - it's the phosphoric acid in it which does the business aparently. Once you have removed the anodising you should be able to polish the hangers using the normal abrasive method of emery and/or wet & dry followed by metal polish. Remember though that once the anodizing is off they will tarnish quite quickly especially if you get road salt on them so you may want to lacquer them to keep them looking good longer.
Using a brush head on a bench grinder is easiest but it may not get into all the corners and nooks and crannies. Using a drill with assorted shapes can get at all of the bits but you will have to hold the pipe steady in a vice with soft jaws. Emery cloth and wet & dry is best done by hand. It takes a while.
If everybody thought like that, then you'd have nobody to pay to do it.
There's no reason why anybody can't do a professional job but it takes time, patience and most of all an active interest and pleasure from what they do.
To me it's a hobby and I get as much pleasure from working on my bike as I do riding it.