Your use of "they" here is misleading. Many, if not most, people in the Gemini community see no need for Titan. The existence of a new protocol doesn’t imply that Gemini is somehow lacking.
A Gemini client that doesn’t support Titan is still a fully-featured Gemini client.
Additionally, your description of Spartan is simply incorrect. There are several significant differences between it and Gemini - the most obvious being that Spartan doesn’t use TLS at all!
Additionally, your description of Spartan is simply incorrect. There are several significant differences between it and Gemini - the most obvious being that Spartan doesn’t use TLS at all!