Sounds like you where using an overloaded VAX then the PR!ME 550 (similar tech and a competitor to VAX) we had at my fist job never had such sluggish performance.
And Vt240 was very much noddy graphics high end then was insanely expensive vector systems from HP os Tectronix
Twenty programmers on one vax and actually doing the simulations is CPU intensive. The VT240 is what our customers had (and they are expensive enough all by themselves; a single VT340 in 1991 was $3600.
My dad brought a Tektronix 4051 home from work when I was a teenager, so that was one of the computers I grew up with back in the 1980s. I didn't realize at the time how expensive those were.
And Vt240 was very much noddy graphics high end then was insanely expensive vector systems from HP os Tectronix