This is true.
Back in 1985 Richard Garriott released Ultima IV after being little more than a year development. He outsourced the composing of the music and some of the art, but he handled the programming alone.
Back in 2012 Bruce showed the demo for Unknown Realms, "almost finished" in five years of development and collected money 1/4 of a million dollars for the last finishing touches. He also outsourced the music and some of the art but failed to deliver anything after 10 years of development
So yes, his tweet is kinda accurate - it neeeds 10x the time and money than it did in 1985 =)