I feel that at this point the bottleneck is our ability to safely and reversibly enhance human bodies with all of the amazing technology we've created in the pa

I feel that at this point the bottleneck is our ability to safely and reversibly enhance human bodies with all of the amazing technology we've created in the past few decades. Maybe this has always been the case, but it seems ever more so now. I can certainly foresee future technology visionaries' frustration with having amazing nano-scale machines with which they want to experiment and push humanity's boundaries, but no way to guarantee that there won't be severe consequence to one's health on the long term.