Maybe.
I was referencing my own realization earlier today, when I was wondering if I can DYI a ground-penetrating radar to scan the allotment garden for hidden "surprises". A ground-penetrating radar is something I learned about as a kid watching a popular science videotape, back then a stupidly expensive high-tech piece of professional equipment.
But it hit me that there are two main forces keeping such technologies stupidly expensive and inaccessible to general public over time: costs of knowledge that went into their design (protected by patents and trade secrets), and specialized parts made in unique way or from unique materials, that don't happen to have alternate applications.
Nowadays, knowledge is not an issue - 20+ years is enough for all the relevant patents to expire, and information to have seeped through to the Internet, available in a combination of Wikipedia articles, textbooks, scientific papers, and blogs, plus we have good LLMs more than happy to synthesize that and transform into a DIY tutorial for dummies.
Which leaves the parts. Whether or not you can DIY such a tech really hinges on whether you can find the critical components somewhere. If they're still unique, you're paying $$$ for procurement (and it makes more sense to try and score broken/used equipment off eBay or something). But there's a chance there's a close equivalent that's part of mass consumer or prosumer device, at which point you just buy it and strip it for parts.
(Which way it is with ground-penetrating radars? Don't know, didn't bother to prompt an LLM with that question yet.)