I know of one ex-colleague who left SG and went back to Msia in the 90s. Came back and withdrew his CPF because SG Govt said cannot keep in CPF anymore. He withdrew and deposit in CIMB bank here. He told me he prefer to keep SGD instead of converting and keeping MYR.
It is just the tips of the iceberg. She probably bought HDB when it was cheap, and then sold for a huge profit. Withdraw her CPF, renounced her PR and run road to lower cost country and live happily thereafter in their golden years. Put yourself in their shoes, these people have more foresight than PAP.