Why have you separated the plugin using extensions and not included it in the core?

This was done for five reasons;

1st is to create a lightweight plugin that is fast, efficient and not bloated with stuff that you may only on some sites or from time to time.
2nd is we want to be able to create many extensions that can work with other services and add features and data analysis that can then be linked back to the listing automatically, where each extension can be just as complex as the core or very simple.
3rd is we want to continue to evolve this plugin with more features and connected services and by having separate extensions will give us the funding necessary to grow this to become a real estate platform that you can use to build client sites and offer more content services to your customers.
4th is having been in real estate none of the other plugins offer functions that can directly assist a realtor by linking the property data with all the top services that are available to them today.
5th is there are lots of different standards and to bundle too many differing options creates horrible bloated and slow software, of goal is to display listings quickly, easily and fast.