I'm afraid most of the value is probably in the lab hardware itself, not the FOSS stack fetishism. As such you'd need to figure out how to ship better and/or cheaper lab hardware to gain market share, when an entrenched provider has already learned how to ship state of the art hardware. If you really believe market forces will value FOSS for FOSS's sake that highly, perhaps you'd like to start that hardware startup yourself? You make it sound so simple... perhaps you already started one? But for most, I think the Hobonson's choice I think you're actually proposing is between:
1) Continuing to do lab work with the proprietary hardware
2) Letting someone else replace you when you switch careers to work on your new hardware startup. Your replacement is unlikely to care as much about FOSS as you (after all, you were willing to quit over it!), and even if they do, their replacement likely won't. The perverse result of this is a decreased demand for FOSS lab equipment, not increased demand!
You might increase supply of FOSS lab equipment. Or (and I think this more likely) you'll go bankrupt before moving the needle. Speaking for myself, I can't convince myself of the untapped market potential of this niche, I don't know hardware, I'd be going up against incumbent experts, I'm not passionate about lab equipment... if I somehow acquired investor funding under these circumstances I would worry I had conned them more than I had convinced them of the merits.
Some "choice".
Better to keep doing lab work if that's what you enjoy, and perhaps agitate for less proprietary FOSS options if that's something dear to your heart. Maybe you'll cure cancer and save the lives of future developers of FOSS lab equipment.
No, because if the same guys would be coding for GNU/Linux, it would mean a closed source binary compiled against a very old C library that most likely wouldn't even start in modern GNU/Linux.
Or try to access kernel features, drivers or pathname that no longer exist in modern distributions.
Using *BSD or GNU/Linux for laboratory hardware doesn't mean that the code is made available, or even if it is, it is cost effective to pay someone to port it.
Many of those XP systems have actually code available, at least in life sciences, just labs don't want to pay to port the code to new systems.
Also the Linux kernel should always be backwards compatible.
You could also place any missing files.
Even if that is all too complicated, you could just use an old Linux distribution or Linux kernel and backports patches for yourself, although not sure if that is easier.
What I'm saying is, it's good to have the choice and option to do that.
Of course, like you say, if you have that option but just don't do it because it takes time / money to do it, then that is your choice.
If dynamic linking was used, the entry points might have been moved, the syscalls have changed, bugs are were being taken advantage of were fixed.
If static linking, the calls into the kernel might have changed or data read from /etc, /dev or other type of expectations from target OS.
No, Linux takes binary compatibility seriously. I can run statically linked binaries from 1992 on a modern system just fine.
ELF was being slowly introduced in 1994, with Slackware 2.0 being one of the first distributions to support it.
http://www.linuxjournal.com/article/1059
So I really really doubt you can pick a static executable compiled against kernel 0.x.y, using a.out format and execute it in Ubuntu 16.04 LTS as example.
Actually, I just need to take the dust out of my Walnut Creek CD's to prove my point.
Not to mention how disparate the file system structure, including device drivers, of something like Yggdrasil Linux 1.0 is compared with modern distributions.
As I said, easily verified by dusting off Walnut Creek CD's and picking a random binary from them.