> $150k in today's dollars. They were very, very expensive.

It's very expensive for a hobbyist, but not very very expensive for a professional lab, which I think would be the target market for something like a Tektronix 576 in 1970. It's basically equivalent to buying a mid-tier 10GHz scope today Which is a normal piece of lab equipment in 2026 for a professional lab. It's not even uncommon to see them in University labs.

If a hobbyist wants an I-V curve you generate a 1Hz triangle wave of current with an dual opamp and use X-Y mode on your scope. More than good enough for the overwhelming majority of hobby applications. Unless you're writing a textbook and want fancy plots, then fine. Use an SMU. :)