It's quite rare in Australia though. This data point suggests that closing all Amex cards so you can qualify for a new SUB every 18 months has its risks.
Amex value a lot about ongoing relationship. This probably happened because OP didn't kept any of the previous Amex cards so Amex has no recent data point to go with.
For OP: Amex is legally in the right here to withhold the sign up bonus unfortunately. Given you have nothing to lose you can contact the escalation channel with Amex and see whether they will give the points to you as a goodwill.
Amex does not ‘honour’ long term relationships. I had been with AMEX since 2003, always paid off my balance in full on time. Went from a 6000 limit to 30k to their ‘limitless’ platinum charge card in 2017 which they closed, on the second month because I put on it, around 20k within the same statement period (mind you, I sometimes cycled about 30k per month prior to that on their credit product without a hitch). They also suspended my wife’s accounts (separate from mine, she was a client for nearly 8 years) the moment she bought something for 50 dollars.
They transferred the owed monies to debt collectors within 3 days of closure, we were overseas. The moment I landed in Sydney the following week I had 20 messages from the sharks, threatening legal action and property seizure to recover the funds. Interest was set at something like 25% and already began accruing.
I tried to reason with amex, no avail. They kept going in circles. It’s all because of an overzealous and racist employee who thought nothing better than to trim us off.
I got the financial services ombudsman involved. They reached a verdict within 3 weeks that amex was within its right to cancel my account without notice and for NO reason at all. By that time I had the outstanding balance repaid in full. The ombudsman did however put a halt on debt recovery, fees etc and interest accruing (as per my initial request).
I also managed to lobby over the points the day they suspended the accounts including the just-credited bonus. Amex refused to refund the annual fee.
I appealed the ombudsman’s decision, or was it a review, I forgot. Anyhow, the final verdict was that Amex was right relying on their ‘no reason’ decision to cancel, with amex acknowledging that I had been a loyal customer with long and clean history. I then got a pro rata refund for the annual fee (but the travel credit got forfeited).
I later figured out that because we had gone on their charge card, none of the previous credit history mattered anymore. The team overlooking fraud just sees: new card, lots of spend -> suspend/cancel. Very rigid business rule. Very weird and amounts to false advertising because theIr marketing pumped the product as a no limit spending (above $50k required pre auth).
Happy days. Not