I don't know; I'm not young enough to remember.
When I was in the minicomputer business, it was maybe 50/50 hardware and software (and that mostly assumes you considered software to include low-level things like microcode). And software people weren't mostly paid more than those in hardware--which is to say generally a good middle class professional wage.
Working with Suns and other workstations as a teen (so my perspective was limited), I caught the very tail end of software as a modest middle class professional wage for everyone doing it (right before the dotcom boom hit).
The people I worked with were really good at what they do, but not strutting like newcomers started doing pretty much the instant the dotcom boom started, and not rich. (Well, one guy did buy a used MR2, and get his private pilot license, but he also lived with his wife in a trailer on an undeveloped parcel. He was a very solid software engineer, working on important stuff.)
I might have inadvertently tried to preserve some of that modestly-paid excellence of the generation before me, but I don't recommend that. Cost-of-living in my area is determined by people making FAANG-like money (well, and real estate investors, and price-fixing), and you have to either play along with that, or move away.
But a somewhat high-flying (albeit hardware) company was recruiting me for a CA job and they basically admitted it would be a lifestyle downgrade in terms of salary.
Some people made a lot of money when dot-com hit. A lot also got wiped out and ended up leaving the industry.
I never had the highs or lows. I was probably making something south of $100K in the late 90s.
I've been given second hand accounts of similar situations. One was team consolidation, and the business was offering Boston-area engineers positions in San Jose. One of the folks who moved with his family was back in MA within 5 years. His salary was not adjusted as much as it should have been for the cost of living difference.
A question, though. Was software designed at Sun closely with hardware teams and vice versa, or were they mostly disjoint? Presumably many hardware companies that have succeeded have built good tooling around said hardware (like NVIDIA).
The low-level software work at Data General where I was prior to the analyst biz was certainly integrated to a certain degree--read Soul of a New Machine if you haven't. The software folks for the minis were also mostly in the same same location. As things migrated to Unix, most of that team was in RTP and it's probably fair to say that there was less integration though probably wasn't something I thought about a lot of the time. Hardware stayed in Massachusetts.