One problem is with the product-as-service. You have a basic product - for example a project management system - but to sell it to the big enterprise clients yo

One problem is with the product-as-service. You have a basic product - for example a project management system - but to sell it to the big enterprise clients you have to add that one feature they need to integrate with their backend accounting system, or put the logo on the right instead of the left just because. With a good design you should be able to customize without losing the integrity of the product, but if you didn't design with that in mind you have a problem. Customer requirements may also go beyond what even a good, decoupled design is capable of. You can therefore end up in the same situation as the consultancies, only with lots of customized, hard to upgrade or refactor versions of your product.