It was a different time:
“Condor plans to spend one year in the development of Diablo. Personnel will consist of: one designer, one chief programmer, 2 junior programmer, 2 art director/artists, 1 illustrator/sculptor, 3 pixel artists, and 1 sound FX person”
So, 11 people for a year for Diablo. Meanwhile Diablo 4 took 300+ people 6+ years. So over 150x the cost, not accounting for the fact that game developers are paid much more now as well. People pretend it’s the same industry but it’s evolved dramatically.