Let's imagine your company has 100 employees in it. So at $5/user a month, you are paying $500 a month.
Now, the median salary for thos 100 employees is most likely at least $3000, so you are paying them collectively $300,000 a month. That represents 0.016% of their salary. Do you get where I'm going with this?
And when the median salary of your employees is $0/month (prototyping or a family domain or something) and your options are:
a. Nothing
b. $50/(employee/family member)
What then? Of course no company paying $300,000/month is going to care about $50/user/year.
Now, the median salary for thos 100 employees is most likely at least $3000, so you are paying them collectively $300,000 a month. That represents 0.016% of their salary. Do you get where I'm going with this?