While LTSPICE and PCB123 are adequate for many engineering problems, they aren't the best EDA tools for electronic circuit engineering. Those tools are available from companies such as Cadence, Synopsys, Mentor Graphics, Mathworks, Ansys, and countless others. And the cost is out of reach for small companies.
The high-end tool companies are not alone in limiting technology's evolution. Another group that frustrates me are the organizations that publish technical journals. Lots of great research is hidden inside articles behind expensive pay-walls.
Perhaps more frustrating is that many of those articles are written by people who were funded in part by grants of public tax dollars through various arms of a government. In the United States that includes agencies such as the National Science Foundation (NSF), Department of Defense (DOD), and National Aeronautics and Space Administration (NASA). The same thing is true in other countries around the globe.
Thankfully, this appears to be changing slightly. The IEEE now has an arm that openly publishes a small amount of research. I suspect, and hope, that this will become the de facto standard in the not too distant future. In fact, all of the world's patent offices have always offered open access to research results.