Why don't Allegorithmic Substances have color controls?

I’ve been looking for brick Substances on the Asset Store and it seems there are dozens of them. However, they all seem to have fixed colours - “Red Bricks” for $15, “Dark Bricks” for $15. They have a “Hue Shift”, but that’s not very useful since it changes the brick, dirt, and mortar colours - which is unlikely to give a useful result.

I want a Substance that I can reuse for multiple bricks in different areas of my game, but it seems I would basically need a whole different Substance each time, which defeats the purpose.

Is this a limitation of Substances, or just a cynical way to charge multiple times for essentially the same thing?

If I bought Substance Designer, would I be able to edit one of these “Brick” Substances and make the colors each a parameter? Could I then sell or give away the resulting Substance on the Asset Store?

Edit: Okay, I have found some that have brick colour controls, so it’s not a limitation of Substances.

Yes, some of them have a color parameter, some don’t, mainly because we had a maximum number of tweaks for the first textures we produced due to compatibility issue with Autodesk Flame.