Actually, video conferencing systems aren't that hard to build anymore. But it is hard to grow them as companies.

Just among my circle of friends there were two startups that made video conferencing systems. One generic, and one for uses that required a higher degree of security. If we move one stratum out, there are about half a dozen startups where friends of friends take part in developing smart cameras for video conferencing as well as industrial uses.

And then there was the Tandberg video conferencing platform which was acquired by Cisco in 2010. (That entire stack was designed and engineered in Norway. From low level DSPs to software).

There are dozens of companies that could make a video conferencing system in Europe today that would be no worse than what you find in Zoom, Teams etc. But since it is a crowded field, they haven't had the muscle to compete.