let's call a spade a spade
legacy solutions can call themselves ‘platform’ all they want, but they’re just behemoth applications with no real extensibility. third-party build-ons are nonexistent, code is proprietary and impossible to wade through, and customizations are difficult to maintain.
real platforms give you options, extensibility, and ownership
it's your software
you don’t have to learn a new application to be able to create your own apps. drag’n’drop the elements you need right where you want them
it's your data
say goodbye to the days of entering data into your system, and then their system, and then submitting into another system. your data is in one place
it's your way
microsoft is platform. by definition it’s extensible, open to development, constantly up to date, and has thousands of resources available