This is misleading. Chase allows only one signup bonus in 48 months for both Sapphire brand cards. American Express offers three versions of personal Platinum, Gold, and Green, plus Business versions of all three. We can earn a new account bonus for each of these eight cards, plus there are targeted offers which do not have previous cardholder exclusions, -and- the "lifetime" period resets seven years after cancellation.
Fair points! I was more speaking for personal experience and how I rationalize things rather than give advice to the OP.
For me, the Amex setup is a little too much for my spending, the credits don't make sense, and the transfer partners don't make as much sense for me since I mostly take economy trips so that's the primary reason I avoid it more so than the sign up bonus rules (though I will probably get the sign up bonuses eventually)