In my opinion, the key barrier is putting together a relatively small cohesive team of relatively like minded researchers together, in the same physical location, rapidly setting up and performing experiments -- on a daily basis.
Bullseye! Most of the progress I made at SRI and most of my residual knowledge (and an awful lot lost) came in the first 2-3 years of the "Fleischmann Pons era" when I had a group of 8-10 highly talented folk focussed coherently, energetically and full time and on FP experiments. With a few consultants added and active participation from our sponsor (EPRI) this group encompassed all skill types we believed necessary to do the job. This group was young (for physical scientists ... at 40 I was the second oldest), and well funded (1-2 million $US / year).
One of the reasons I am skulking (very happily) in New Zealand is that I cannot play that role again. I am too old, lacking both energy and imagination. Oh I pick a few things up and the residual knowledge helps, but I do not have a dozen people (and an entire research institute) around to bounce ideas off, culling the weak and tuning the strong before entering the lab. But my intense frustration and the reason for three stern ICCF lectures (ICCF19-21) is that I know a half dozen people out there who together have what I believe is a sufficient collective skill set to get us easily to the next phase (which I see as a working demonstration). And, as I have said before, money is not a problem. This would take 3-5 million $US / year for 3-5 years (and I know how to budget research - I did it successfully for nearly 40 years). That amount is easy.
So what is the problem? I have blamed "secrecy" but that is just an excuse. The real reason is ego. Some of it is an individual desire for credit. But almost all of the pushback I have had against assembling my "dream team" is from the sponsors. On one side the people with the money do not appreciate that scientists (and engineers) are not mutable ... one cannot be substituted for another. The people we need for this job with the skill sets and attitudes are precise - some unique. On the other side men or organizations with money are ego driven to be "first" . If they feel they have control (by money or NDA) of a unique individual talent they cannot (apparently) be persuaded to pool this talent for a common good.
So we wait, hoping that one or two of you in teams of one or two will get across the goal line. It has happened before. Someone mentioned Tesla above, and Martin and Stan were a team of two. But Tesla and Fleischmann were both geniuses ... and I know Martin had an extended and very able scientific family (albeit most not believing that "cold fusion" was an idea worth their time). Please don't ask me to identify my "dream team". This would embarrass some (whether on the list or not) and make the job harder by corporate pushback. But I concur precisely with "Director's" quote above. Which reminds me - the team would need a good director - and that is not me.