Why would scientists ignore results that could lead to limitless power, tons of money, and even Nobel prizes? That will be hard to explain.
It is not a bit hard to explain. Look at the way the scientific establishment reacted to other breakthroughs that hit them in the pocketbook, such as the NMR or the discovery that helicobacter pylori causes ulcers. It is all about money and power.
After all, they rushed to duplicate and study F&P's research when it first came out.
Very few scientists tried to duplicate. ~130 groups did, worldwide. 92 of them were led by qualified electrochemists. They replicated within a year. The other ~40 groups did not include electrochemists, and they all failed to replicate, for obvious reasons. There was never the slightest chance most of them would succeed. They made ridiculous mistakes, such as confusing the anode with the cathode. As I described it, they were trying to tune a piano with a sledgehammer. See:
http://lenr-canr.org/acrobat/WillFGgroupsrepo.pdf
http://lenr-canr.org/acrobat/RothwellJlessonsfro.pdf
Unfortunately, the groups that failed to replicate were led by influential physicists at important universities and national labs. They were published in places like Nature, and the electrochemists were shut out and attacked by Nature and Washington Post.
The three most influential groups that reported failure actually succeeded, which is some of the best early proof that the effect is real. Harwell replicated nicely. They cooperated and gave the data to Fleischmann, who showed there was excess heat. Caltech replicated and then made a stupid mistake, hiding the excess heat. MIT held a party celebrating the death of cold fusion, then they replicated and found it worked, so they published a fraudulent version of the data erasing the heat. See: http://lenr-canr.org/acrobat/MilesMisoperibol.pdf These were the archenemies of cold fusion. They would have lost hundreds of millions of dollars in funding if cold fusion had been accepted. They did all they could to destroy it, yet even they succeeded in replicating -- inadvertently, of course.
I propose a better reason: most mainstream scientists who are properly qualified and have looked at LENR are convinced from the available results that LENR has never been properly demonstrated and may, in fact, not even exist.
You are incorrect. You need to read the experimental literature, the history of cold fusion, and the opinions of the mainstream scientists. You will see from this that the mainstream scientists know nothing about cold fusion. Like you, they have read nothing and they have no idea how the experiments were done, what instruments were used, or what results were obtained. Their assertions about the experiments are ignorant nonsense.
The results were properly demonstrated. No one has discovered any errors in any of the major experiments, which were published by scientists in 180 mainstream laboratories, in peer-reviewed literature. (They were published eventually, despite tremendous opposition.) If the opponents could have found errors, they would have published papers pointing them out. The only paper like that was by Morrison. I think it has no merit. Read it and judge for yourself:
http://lenr-canr.org/acrobat/Fleischmanreplytothe.pdf
The only other "objections" were published by Shanahan, who is a member of tin-foil-hat school of cloud-cuckoo-land physics, where anything goes, and anything might be true. See: