While I don't pretend to understand its details the conclusion of the article "Sharing of Very Short IBD Segments between Humans, Neandertals, and Denisovans, by Gundula Povysil, Sepp Hochreiter." is one that's encouraging.
"we expect that the analysis of the population structure by sharing patterns of very short IBD segments will become an increasingly important method in population genetics and its results will become more and more ﬁne-grained."Progress in population genetics provides hope for improved application to genetic genealogy. Developing techniques for matching shorter autosomal DNA segments should mean being able to identify a larger population of genetic ancestors and so a greater probability of detecting matches with genealogical ancestors.