I spent a lot of time doing business in peninsular Malaysia in the 1990s. (I also wrote a booklet called “The Road to Profit: Investing in Malaysian Property” and therefore did some research into business and society. My booklet, of course, painted the rosiest possible picture of the country.)
IIRC, the ethnic Malays, known locally as “Bumiputera”, who made up the majority agrarian classes, and urban poor, were given various “positive discrimination” concessions to counteract the anti-Chinese race riots of the 1960s.
For example, by law, every foreign-owned joint venture has to have a 30% stake owned by a “Bumi” - which situation reminds me of Arab involvement in foreign-run businesses in the Middle East (namely workshy, inexperienced, but raking in the profits regardless, purely because they can - this impression, again, is my observation, not borne out by any data).
There is also an honorific and hereditary system of “royalty”, which which comes state governance, that is dominated by Bumis. There are a great number of “Bumis” in positions of federal power - all Malaysian prime ministers have been Bumi, for example. And political dissent is famously not tolerated, despite the country’s lip-service to democracy. Political Bumis have a reputation (note again I only say reputation) for corruption, laziness, etc. Nothing I saw in my travels there disabused this notion with regard to the politicians and dignitaries I met. I used to hang out with the former Dato’ of Johor Bahru and he was one dodgy bastard, making a small fortune from investing state money for personal profit. But a small sample size.
The ethnic Chinese, of whom some were part of the historical diaspora, but the majority of which were invited in by the British to stimulate local economies, are predominantly mercantile Cantonese from the merchant classes in southern China - in other words their predecessors weren’t necessarily peasants at the time they migrated. Cantonese people have joked to me that they and the Jews are always the first people to arrive at any new geographical economic opportunity and get things running, and I think there’s a grain of truth in that (anyone know if there’s a link with that anecdote and the popularity of Mah Jongg among American Jews?).
The greatest amount of racism I saw there, though, was from both groups towards the minority ethnic Indians. They were employed almost exclusively in menial roles - cleaners, street sweepers, toilet attendants, and were largely ignored or barely tolerated by the people I met there. I found that aspect particularly shocking.
The above is anecdotal and is merely generally representative. I also met lazy Chinese and hard-working Bumis and Indians in positions of power, but they were in the minority in my experience.
None of the above do I attribute to genetics - it’s cultural in my opinion. The overwhelming influence of family and culture, merchant-class Jews and Chinese for example, on any given individual I feel sure would counteract any minor fluctuations in genetic characteristics.
BTW there is nothing I have ever read to indicate that Malaya “kicked out” Singapore. I had always thought that Singapore left Malaya voluntarily to avoid the pro-Bumi laws on a majority Chinese state.