There was a period in computer history in which so called Unix workstation were the most advanced desktop computer available. Around the year 1988 the Apollo/Domain workstation series was sold for around 150k US$. These machines were used for CAD, programming and text processing tasks.
The interesting situation is that only a few years the former workstations were no longer needed. Instead the PC together with the Intel 386'er has replaced these machines. Intel 386'er PC were sold for less money and provided the same and even more performance. The more abstract reason why Unix workstations have become obsolete is that the user is not interested in a certain use case but he prefers computer technology with a certain specification. It is measured in Megabyte for the RAM, the amount of MIPS for the CPU and very important the amount of megabyte on the harddrive is determined. The ibm compatible PC has provided the better price to performance ratio.
The main reason why technical unix workstation were available in the 1980s was because of historical reasons. The idea was to compress former mainframe computers into a desktop case and this was equal to the birth of the workstation. In the mid 1980s the normal IBM PC was too slow to replace former mainframe computers. The first IBM XT model was shipped without a harddrive and the processor was very slow. In contrast the existing minicomputers and mainframe systems were much powerful in the late 1970s. So the workstation was connecting both worlds.
The reason why workstations are interesting for today's users is not because of the hardware but because of the unix operating system. Unix was improved into the Linux operating system and it is used on today's computers frequently. Porting Unix to the IBM PC was an important milestone in the computer history.