First, the disclaimer states that past performance is not indicative of future returns but this is precisely what the graphic is trying tell people.
Next, historically a very large percentage of fixed income returns come via the coupon. Obviously today the income portion is at or near all times lows, therefore much less carry to insulate potential price declines.
Further, the aggregate bond index is longer (higher duration, greater price sensitivity) than its ever been. This works both directions, but similar moves in rates will lead to larger changes in prices versus prior history.
and maybe most obvious is that this looks at nominal returns versus real returns. A buy and hold investor of a 10y UST would lock in a negative real return assuming inflation expectations materialize.
Yes it’s technically true, but for today’s average investor I think it paints a very misleading picture.