In my home studio I have all Presonus controllers, and I can say that an S4 or S6 will not interfere with the sales of Presonus products.
Top professional engineers and producers are the opinion makers. High-level engineers will never abandon consoles like the S5, S6 or S4. And they are - I'll say again - the opinion makers in favor of Studio One. So, it will cost Presonus nothing to implement this since the Eucon protocol is opened by Avid.
And then many professionals will migrate to studio one, given the facilities and quality of the software.
Please Presonus, do it this month, this can be done fast! You're losing this great opportunity to gain new top-level users. And there's almost no cost at all for Presonus.
I am a mixing engineer at Cinecolor Digital, one of South America's biggest post-production studios.