I do believe better gear could have made my earlier shots better. I started with a 450D and kit lens, then got the 100mm macro, then the 16-35 and 100-400. The 16-35 enabled better landscapes. The 100-400 enabled bird photography. I spent a lot of time trying, learning, and experiencing the limitations of my gear (like 3.2fps and basic AF.)
I always feel as though I'm experiencing one limitation of my gear or another. When I got the 7D, it was the most liberating camera purchase I'd ever made at the time. It made the 100-400 lens work.

If I'd started with the 7D, I do believe I'd be farther along in my photography than I am today, as I'd have been able to spend more time learning about the nuances of bird photography, rather than the nuances about how to get around the limitations of my 450D.
You probably always learn, and can probably always progress, regardless of the equipment in hand. However, I strongly believe that when your not learning how to get around hardware limitations, your learning how to actually do the kinds of photography your interested in. Moving from the 100-400mm lens to the 600mm f/4 lens was another liberating experience. I haven't felt the limitations of my gear nearly as much since the 7D and 600mm. Even adding the 5D III to my kit has not nearly had as much of an impact on my work as those other two additions. It's opened options for astrophotography, and allowed me to use already-existing skills to get close to birds and get better IQ in the process, and allowed me to fully utilize the capabilities of the 600mm lens. But it just hasn't had as much of an impact overall...as it really didn't eliminate any key limitations that I have.
Most of my limitations now, are just myself and my skill level (with the exception of astrophotography...still have LOOOTS of hardware limitations there.) Every time I go out to photograph birds and wildlife now, it's me learning how to photograph birds and wildlife...and much less about learning how to use my camera, or work around my camera.