- Most people have never thought seriously about the topic, for various reasons
- There's a lot of really ill-thought-out content in the mental space life philosophy should reside that amounts to things that are emotionally satisfying to believe, convenient to believe, or traditional to believe
- There's a lot of "common-sense" knowledge with accompanying slogans that people have to abandon in order to look into life philosophies
- Life philosophy is categorically different from other fields of thought in that there is very little hard fact in the discipline (it is divergent, for starters)
- Many people, seeing the ill-thought-out content, consider the entire field to be bullshit and think they can escape it
- A rich and powerful life philosophy with the ability to mimetically defend itself grows best in the soil of autodidactic, eclectic, well-read, soft-tempered, self-skeptical people, who are in extreme minority
- Pursuit of a life philosophy takes one far enough off the beaten paths of society that creation of significant content of any kind distances one from society.
- Life philosophies are divergent, so apart from those who decide to be inspired by another philosopher or who agree to form company with each other for reasons other than their direct philosophy (e.g. metaphilosophy, agreement to listen and consider and comment, etc), the only commonalities that are commonly built are the result of getting followers
- Followers are not companions, and with rare exception they limit the natural growth and change of a philosophy and are very unsatisfying for a philosopher.
- Dragging people out of the mainstream and discussing/developing the particulars of one's philosophical interests are two very different activities
- Being fair, careful, and thoughtful and beating down endless repetitions of poor arguments for naïve and common perspectives require two very different aspects to one's personality
To a certain extent, this applies to things a bit outside what most people would consider life philosophy. Very few biologists will bother spending time defusing arguments that young-earth creationists construct.
Some of the happier times in my life were when I had groups of people who gathered regularly to discuss philosophy - their philosophy. People brought some ideas to the table about whatever they liked ("I've decided there's no such thing as empty space", "good samaritan laws are a formalisation of existentialist ethics", etc), they talked for a bit, we discussed how the idea might be useful, if we liked it, occasionally someone would argue against it, we'd go back and forth over tea and light snacks. Generally small groups, occasionally some christians would join in for a few sessions and then wander off (but a few stayed, in one of the groups). People with "hard" philosophies tended not to come back after one go. Finding the right kind of people for this is incredibly hard, and keeping the tone right requires the group to get and keep traditions that assist. This is another thing I miss.
The atheist/agnostic groups I've been part of at times have been different in character - much larger, split into political/philosophical blocs, more structured use of time, and generally focused on science or advocacy with only the occasional foray into divisive topics. These haven't been as satisfying, although they were socially really nice - having lack of religion and a positive attitute towards the sciences out of the way made finding dates a lot easier for most people, particularly when secular humanism acted as a dominant (although by no means sole - I never was and am not a secular humanist, even though I have substantial enough common cause with them to support their institutions) political/personal identity for many in the group. I don't think this sort of group tended to be "safe" for good philosophical discussion though, particularly when a good segment of the group were of the "I don't like moralising or philosophy which is why I left my old identity" type.