Milo > i m from HK too, i will say that cases like your colleagues do not make up the majority. most PRs working here are normal working pple like you and me. i m drawing local package all the while, btw.
from what i understand from my other friends, in most cases, once they convert to PR and contribute to CPF, the housing packages will be withdrawn. Rationale: when they are on EP, they do not get employer's CPF contribution. So company use this money to make up and become their housing benefit. Once become PR, employer contributes to CPF which supposedly can be used for housing purpose, and the housing benefit is withdrawn.
The PRs with high cash are those that sell everything back home and come to SG. these pple are normally cash rich and CPF poor, while locals are the other way round. in this light, you can say that they do have a slight advantage, as they have more cash to be flexible and decide whether they want to use the cash for downpayment or COVs. Hence, many of them go for places where flat valuation is lower, so that they can chiong on high COV and still maintain a relatively low overall flat price.
Also dun forget a large no. of PRs are pple that studied in SG and subsequently work here, or young pple that come straight to work in SG after graduation. These pple are in no better situation compared to locals - equally cash poor
As i mentioned, i hope to provide some alternative information becos i observed that many of the info provided on channels like internet forums are very one-sided, with mainly locals stating their frustration and no PRs dare to clarify their situations.