In my own personal opinion, many of the components for an AGI of average human-level intelligence will likely be tested and functional by the end of the decade. Something publicly demonstrable likely by the early to mid 30's. From there it'll depend on how much testing is required, method of distribution, current laws, and more as to when it will be publicly available.

I think that we have the concepts down, but development of the software and hardware (two separately developed things) will take more time (maybe by the end of the decade), followed by extensive testing because it will be a very complex system. The processes may be simpler than one might assume, but a lot of data will still be involved, and obviously the dangers need to be mitigated. So even if the software and hardware capabilities converge, and the architecture 'works', it will still need to be tested A LOT. Not just for dangers, but even just making sure it doesn't hit a snag and fall right apart... So even if we as a species technically have it developed in the next 10-15 years, it may take longer to get into people's hands. The good news is, I think it's virtually a 100% guarantee that it will happen, and sooner rather than later, and it will be widely available and I think multiple people/companies/organizations will develop it in different but viable ways. After that it'll be up to the people whether or not they believe any of it. No definition will satisfy everyone, so there will always be those that deny it even when it's here and they're using it.