I think you have a fundamental misunderstanding of how bonds work. What you are saying is mostly true, BUT the coupon rate is set at bond issuance. Meaning if you own a bond now, and coupon rates go up because of an event, your rate does not magically adjust. When event like you describe happens, it means it's a good time to enter the bond market.

What Dalio is saying is that currently real returns on bond are rock bottom or even negative. So why would you own them? He's not saying to NEVER own bonds, just that it currently does not make sense. If in the future, bond coupon rates increase, then it will once again make sense to own bonds.