Personally I "think" I want to just code forever, but I migrated from coder to more of an architecture role. However, for me, the growth is just not there. It is in the cross-collaboration, mentoring and industry influence is how you develop. In some companies time in grade is a factor in layoffs. Due to ageism companies might not be looking for someone at a certain age and experience to just grind out code full-time, but to work on a product holistically.