Some skills required for running a business will never go out of fashion. Selling and leadership, to name two. These skills are required at each point throughout a company’s lifecycle, whether you’re just starting or are heading a company that has existed for decades.
Some positions or roles within a company facilitate continuous improvement of those skills more than others. Training opportunities might not present themselves. If so, they should be actively sought out. A side business or project could be fertile ground for brushing up those skills.
Always embrace learning opportunities.