I believe so much of tickling is psychological. For me, it has increased overtime, but I think that is a direct result of engaging in therapy and putting in a lot of work around self acceptance and self love.
In doing so, I think I’ve been able to connect with my feelings, both physical and mental in a different way, and I’ve allowed myself to feel more vulnerable, which has led to feeling more ticklish in a session.
I think sometimes it might feel like it is going away because we don’t have the same physical opportunities, or because we are highly focused on stressors and anxieties, among other things.
Just my personal experience.