Depending upon the vendor, the tax can be pretty big. It largely depends upon the product lineup of a given vendor.Diversifying your portfolio makes a lot of sense but what is the tax on that?
DMS's want a tax so that other vendors can access the data via api.
Then you also need to pay attention to how fast other vendors can match changes to the data structure that your primary is doing.
I would like to see diversity in this field because it clearly opens up the ability for competition.
It would be really nice if everyone would just get along for the good of the industry rather than trying to trap clients by not respecting the dealer's philosophy as it relates to vendor choices. But, that isn't the world we live in...for now.
Here's a new business idea for someone OTHER than me. Build a "connector platform" similar to Zapier that is geared toward Automotive. Build a connector application that does nothing but link Company A products to Company B products. Any conversions that need to be made will happen in the connector, and voila...we are seamlessly sharing data! Ha!! Good luck getting anyone to come to the table for that!