Engineering never went completely to Windows NT.

Between 1997 and 2007, I worked at 3 different companies, in 3 different countries (2 in Europe + Israel) as Design Engineer in electronics.

All the serious engineering programs for EDA/CAD were run on Solaris and accessed from Windows with X-terminal programs.

Towards the end of that decade, the Opteron-based servers were both much faster and much cheaper than the Sun servers or the Fujitsu servers, so the EDA/CAD programs were migrated from Solaris to Linux, while the Windows computers continued to run only the X-terminal programs for accessing the servers.

At the beginning of that decade, I also used a Sun workstation, but those disappeared after 1999, because they were much too slow in comparison with a PC with Intel Pentium III or with AMD Athlon.

It is likely that the reason why those EDA/CAD programs did not have Windows versions at that time was that they already required a lot of memory, typically much more than 4 GB, so they migrated from Solaris to Linux only after the availability of x86-64 servers, while having a Windows version was not possible before mid 2006, when Intel joined AMD in providing 64-bit CPUs even for PCs, not only for servers, so the market share of 64-bit PCs became non-negligible.