That is exactly why the mainstream does not think LENR is real. How could it generate all these marginal results (repeatable) and never a large repeatable result? Nuclear reactions, whether detected through excess heat, transmutation, or radioactive intermediates, are awfully easy to detect, and allow the X10 method.
What is the "mainstream"? Anyone with a PhD and an opinion? I would normally assess the mainstream by seeing what is being published in journals. Since about 2005, a decade, this has almost entirely been positive on the reality of the effect. At one point I counted peer-reviewed reviews of the field, since 2005. There were about sixteen, all positive. (I used the Britz database to determine this, but excluded one journal that specializes in fringe claims.) There are now substantially more. Shanahan is here complaining that he can't get his work published.
That's a clue. Now, diehard skeptics will say that this is because nobody with any sense will put in the time to refute this nonsense. At some point, however, that excuse gets very old. It's been a decade. All we see of the strong skepticism is commentary on the Internet, and, then, occasionally some reporter asks a scientist who has no idea about cold fusion but what he got from newspapers more than twenty years ago what he thinks. In the journals? It is dead as a doornail.
"X10 method"? If one Celani wire gives marginal but interesting results do the same experiment with 10 wires. 10X the output. Etc.
Don't confuse Celani's work with what has been extensively confirmed. Yes, that would be a method of testing Celani. However, one thing must be kept in mind, particularly when attempting to apply this idea to PdD work. Pons and Fleischmann scaled down, because they realized they had little or no control of the reaction. That centimeter cubed of palladium destroyed the apparatus and burned a hole through the lab table into a concrete floor. What if that was only the low end of what might happen? After all, this was suspected to be a nuclear effect, and the available energy, once nuclear reactions are on the table, could be enormous.
No, the goal has been to generate effects large enough to measure, above the noise. The difficulty of control, still very real, militates against scaling up.
Skeptics discussing all this tend to lump it all together, as if NiH and PdD were the same. There is no clear nuclear evidence for NiH, the Lugano test provided, at most, one data point and suffered from a while series of major shortcomings.
So, if there were a real effect it is very difficult to understand why by now it has not generated real results. As has been pointed out there are some competent LENR researchers with good equipment. Note that this has nothing to do with theory or not seeing how LENR could work, it is purely a reflection on the experimental results.
It has generated real results, and has since the beginning. However, precisely because of the variability (which Pons and Fleischmann, unfortunately, didn't make clear), there is little exact replication, and there is the additional problem of controlling the material, which is extremely difficult.
That is why the strongest results are with heat/helium, where variability in the reaction rate generates self-controls.
One step at a time. Is the reaction real? If it is, then work to explore how it happens becomes appropriate. We know it is real, but there is, in fact, an aspect of the "mainstream" where it may still be true that cold fusion is rejected. Funding, and, in particular, any funding through the U.S. DoE, which has ignored the recommendations of its own panels. We think there has been some substantial undue influence from the APS lobbyists, but they do not represent "mainstream science," but a particular subset of the scientific community, one with much to lose if cold fusion is real and can be made practical (which are two separate issues).
Cold fusion doesn't need plasma physicists, nor does it need Big Science, billion-dollar a year boondoggles. On the other hand, you gotta love those enormous machines. If the measurements are accurate, however, cold fusion has already generated higher COP than these things.