There are more and more graphics processing programs, from the most popular Photoshop to less known and free ones like Inkscape. Professionals usually use one or two proven programs, which translates into their high productivity.
In the work of graphics or DTP operator you usually need a program for processing vector and raster graphics. You can also include word processors, programs provided by print equipment manufacturers, to the pool of programs needed for such work.
About printing companies
Paints, inks, paper, toners, foils and other consumables - these are things that can not be missing from printing plants. They are ordered wholesale and also consumed in bulk. For each order, the production costs are optimized, and the appropriate technique and type of printing is selected.
Graphic designers, DTP operators and printers deal with this. They are responsible for the quality of the printout and as soon as something is wrong they are the first to be targeted by the dissatisfied boss. Their work is quite hard and I have to admit that you have to really have a fuss to do it. Work after hours, maximum focus and responsibility - definitely not work for everyone.
Who today does not have a printer at home. Their prices are becoming more affordable and operating costs lower. Multifunction devices offer increasingly larger scanning resolutions, less margin, larger formats, etc.
But still, such home printers are far behind the professional equipment used in professional printers. Not to mention the much larger range of techniques used, which have nothing to do with those we know from home printers. Printed roll, solvent, water, anhydrous - long to exchange. The quality of such printouts is higher, which entails the obvious higher costs of printing itself.