I haven't had any trouble with Pothos cuttings up to 5 feet long. We're just guessing but I suspect the trouble with the cuttings is how it was said that the mama plant is not vigorous. From what I've seen, vigor is the key to propagating anything. Starting below that benchmark = starting with a struggle. Sometimes trying anyway is the best option and I believe that is what we have here for Sharon's plant. In that situation, I agree it's possible that they might be doing better if they had not been so long.
The pic that I put before was leafless chunks of stem. I did not leave all of that attached as very long cuttings, because that would have defeated the purpose of cutting them off - because they were naked. If the leaves fall off of a cutting, I would cut it again & redo the top. It ain't over until there's nothing green left.
This pic is a pot I put together 2 weekends ago with some Pothos and Philodendron stems. The Pothos stems had been cut about 6 weeks before. The longest Pothos of this batch is at least 4 feet.
I was going to do an around-the-room thing with this plant, pic taken in December, but ended up having to move it. The vines starting to go across the top of the window are the cuttings shown in the new pot.
The other pieces came from this plant. I cut them off @ the soil level. When cut, they had grown about a foot longer than when this pic was taken.