This is true. One way to combat it I've found (as a CTO) is to ensure backend engineers are involved in the initial pre-mockup conversations and mockup iteratio

This is true. One way to combat it I've found (as a CTO) is to ensure backend engineers are involved in the initial pre-mockup conversations and mockup iteration conversations and to give them just as much vetoing power as someone from bizdev. In some orgs this is impossible but it works great for us. I also find that backend people tend to have extremely good ideas when it comes to UX (better, even, than a lot of UX people), they just don't enjoy or aren't good at executing these ideas (or aren't allowed to). The takeaway is to take your backend engineers' opinions seriously and let them touch the frontend when they want to.