From customization to configurable platform: theory and practice

Small company is ready to do everything to satisfy its first customer. With new customers the experience grows and knowledge of customer's business model increases. With an increasing number of projects in the portfolio company no longer wants to spend many efforts to create and maintain the same features in different but similar such systems.

Solution seems obvious: move away from the independent development of systems and put all on a single generalized platform.

But is it just really? What challenges face analysts, product owner'y and project managers? How do they need to change their thinking and what to expect from the customers?