In reply to gravy:
I have neither the tools, the materials, the time nor the energy to make a decent number of good holds.
To build the wall required some 2x4, a few sheets of ply, some screws, some bolts, a drill, a screw driver, an allen key, a tape measure and a couple of clamps. All tools that I had.
I do not have: a circular saw that is adjustable to the desired angle of the hold, a power sander, a Dremel, a countersink or any suitable spare wood etc etc.
The point of having a board at home is to enable me to train effectively even when I'm limited in free time. I've made between 5 and 10 holds for my board. The ones I have made turned out well eventually but each one has taken the best part of an evening to make, put up, take down, tweak, put back up etc etc. Due to not having the ideal tools for the job, it's tiring work meaning I'm tired after and can't train well that day.
Or, I could go to someone like Silly Goat, Beastmaker, Hardwood Holds etc etc. I can tell them what my board set up is, exactly what hold types I require, how hard to make them and a few days later, they arrive. They feel great, they look better than my attempts, they are right first time, I have supported a small local business, and I can get on with training, which was the whole point all along! And all for a fraction of the money that it would cost to buy the tools I would need to do the job properly.
I did decide to source the materials to make my own footholds because I could get them cheaper myself. In hindsight, I should have spent the very small amount of extra money and had 4 extra evenings of training.
If you enjoy making your own holds and have all the right tools and materials, then great. But a lot of people would have to value their time pretty low for making their own holds to make sense financially. And the climbing hold companies are really good at what they do. They've already put countless hours in to improving their products and seeing what works well and what doesn't so their customers don't have to.