The cost of making graphics doesn't come from the software prices (which are always a drop in the bucket for companies anyways as that's generally one time expenses or they can usually procure bundle business deals) but rather from the amount you have to pay your modelers & texture artists.

Modern 3D graphics require much more time investment as you're setting up more polys, creating more advanced animation rigs, and creating much higher fidelty & better looking textures. This requires more time than the past, which is also usually offset by getting more of them (rather than increasing overall dev time), which means you are paying more people more money which makes it more expensive.

The software costs in about anything from a company standpoint is never the prohibitive cost.