Hi gcrain,
I don’t think that memory foam has fallen out of favor and it’s still the most popular specialty foam in the industry. Latex is more popular in some areas of the industry (such as smaller local manufacturers who in some cases have been manufacturing latex mattress since before memory foam even existed) that aren’t as affected by the marketing that goes along with memory foam or its newest variant gel memory foam but they are very different materials with very different properties and the choice between them is really about personal preference (see post #2 here).
Phoenix