Let's be brutally honest here, cash bonds (as has been described here), don't really increase your income by very much in practice.
The real income you earn is based on the interest rate you get on the cash bond, which I would guess is something very small eg. 3-5% pa.
The rest is just a return of your principal in yearly instalments.
As per the example used of the 100k cash bond giving you an "income" of 23k pa (ie. 20k of your principal and 3k of interest income each year).
If lenders can't see through this sort of "smoke and mirrors" as Rolf calls it, then investors can play/game the system according to these lending criteria.
How long and with how many lenders this will be possible is anyone's guess though.
If this is central to your long-term investing or retirement strategy I think you are taking on a significant risk.
And from my reading these cash bonds are different to traditional annuities (eg. from Challenger Financial Services etc.), of which there are lots of varieties, and don't all automatically return your capital back each year in this way (or at all).