Ah good point, it slipped in my mind as well. I will get a case opened to get them removed from the web page.
The main reason the MSR was EOSd without a direct replacement, is two fold (actually kind of three). 1, component hardware is no longer available to actually build the units. We get notifications of components and do a 'last build' before the EoS, which is based on run rate, etc. 2 (and 3), the actual OS was based on older 11n Phy and to port it over to 11ac Phy would have required a near complete re-write of the underlying code. The existing sales numbers did not justify the development costs to bring it to 11ac and keep the features, when 90%+ of the use cases and existing deployments could be done with AOS. Additionally (tied to #2 and 3), there were more and more security requirements from customers that were not built in to the MSR platform and is part of what added to the large development costs that existing sales of the platform just wouldn't support.
On top of that, the MSR products were much slower than what our current 11ac mesh products support. And while it requires more hardware, to put in a linear hop multi-channel mesh node to support two hops and dual band access, the AP-27x solution (and certainly now with the AP-36x solution) carries a lower overall cost, both in list pricing AND most importantly in installation costs. A single MSR4K with 2 directional antennas and 2.4/5Ghz client access antnennas + installation costs is MUCH higehr than three AP-277s/275s or 274s+275/277, etc. With the introduction of the AP-36x (which was primarily built for the ETSI environment in the EU), that cost differential gets even bigger.
So a TL;DR is 90%+ of the existing MSR deployments didn't actually use the true L3 mesh and oehr advanced MSR features. Most MSR deployments could be served by AOS AP-27x/36x with more performance at a lower overall cost. That said, there will be some capabilities lost (mentioned above), and while that is never desired, was just unavoidable.
With AOS (the following is not supported on IAP), Wiring multiple APs back to back, you can wire APs to support multi-channel linear mesh OR you can certainly wire a dual band client AP and backhaul over a separate mesh link PtP.
Your local DE sales team may not be the most MSR-knowlegeable, but they should be fine with AOS, and if not, they can reach out and include me (the Outdoor TME) directly for any additional support you or they may need. I know though of more than a few SEs in DE that are very strong with mesh and outdoor. :) You can send me a PM as to your specific region and I can get you in contact with the SE Manager for that region to make sure we get you covered. Thanks!