The problem with that argument is that nowhere did environmentalists in the 70s or 80s prevent nuclear power plants from being build. Nuclear has received much more subsidies than solar or wind ever did (even if we ignore the indirect military->civil subsidies) and it still never became economical. Back in the 70s and 80s coal was much cheaper, and now solar and wind are so much cheaper it doesn't make any sense to invest in nuclear. The nuclear power plants that were build, got built largely for political reasons (energy independence, and military), and the reason why not more got build was not those pesky environmentalists, but that it was expensive.