We carved a role for that at my current startup (dev team ~10 people). We maintain a technical roadmap, which includes platform improvements, dev tooling, infra, etc. Other team members jump in to help out if there's something they're particularly excited about or can do well, but one person is dedicated to this work.

Most large companies have teams for this. I've found that the earlier in a company's life you add someone dedicated to this the better.