Yep. I was recently looking at building an art project that required a gas valve that can freely rotate while under pressure.
If you need one gas line, you can get a swivel for a normal shop hose reel for $15. If you need two gas lines on the same axis, the part is similar but way lower volume, so you have to go to a specialty supplier and the price is $350.
The business that makes hose reel swivels makes lots of high volume parts, has lots of competition, and needs to charge close to cost to sell them. The business that makes specialty gas swivels for industry that offers multiple gas lines in one swivel, lots of different options, and makes them higher quality needs to charge a lot more to keep their business operational.
By robot standards, $25k is not a bad. Most mobile-manipulator robots cost 5 digits or more, mostly due to the small market, high materials and engineering cost, and general headaches of robot building.
Now in all fairness, open source tends to mean cheaper because it does reduce how much has to be invented in-house, and also (sometimes) because it lets you crowd source free labor. In software, that can lead to stuff getting completely built for free (or close) because the base costs are low and mostly consist of labor that some people might be willing to do for free. In hardware, it's likely that open source still reduces the costs, but... you can make a thousand copies of a library for free; making a thousand copies of a part is never going to be free.
I’ve been getting back into robotics lately and one thing that’s rubbing me the wrong way is these days, with PCB way, everybody seems to be making their own boards. Why? Some boards are innovative, but how come everybody needs their own FOC controller? Can we get one project going and focus on that before adding yet another FOC controller, but this time with wireless!