It is not like that. The mid-range market is very much alive for A-brands like Keysight, R&S or Tektronix. A couple of weeks ago I visited an electronics lab and factory in Taiwan. Not a single piece of test equipment from Rigol or Siglent anywhere. When I asked about it the tech told me they simply buy Tektronix or Keysight like everyone else. They can't be bothered going for the unknown.
When we were still working before retiring and starting up our consulting business, same was true, everything we had was HP/AG/KS, Tek, Fluke and R&S.
However later after retiring and having to spend our "own $" rather than companies, we needed to do more investigation. Took the plunge an went with "other" brands like Siglent, then Instek, Korad, and Rigol. Not disappointed with any of those decisions, in fact some TE was a delightful surprise
One thing to consider when working at a big company, many get massive discounts on major brands and thus pay nowhere near what the smaller folks pay. This of course is not public knowledge and assume each major company has negotiated special discounts with various TE OEMs.
When your overall company general purpose TE budget was well over $10M/yr 40 years ago, you can imagine that "special arrangements" were in place with all the big TE OEMs!!
Another consideration is the equipment "origin" may dictate whether it's allowed in "certain" labs or even within the company facility
Best,