A bubble is when investors are making lots of money off other investors by trading stuff that isn't worth anything. Risk is being grossly and broadly mis-assessed (deliberately or inadvertently). The bubble pops when people realize this.
In that sense, "majority of startup companies will end up losing money" is actually not a bubbly thing at all. Bubble mentality would be "most startup companies will IPO for huge valuations within a few years."
Ok, not "exactly", but come on: "the majority of startup companies will end up losing money" sounds like a very bubbly thing.