Oh sorry. Perhaps you mean that speaking bad English is sell-out but speaking good English is buy-in?
Anyway, I wouldn't worry about the survival of English or Chinese in Singapore. It's just a little island with 4 million (1/3 to 1/4 non citizen). Anybody wishing to learn good English has the US, Britain, Canada and Australia to look to, and anybody wishing to learn good Chinese has PRC and ROC to look to. Even for Malay, it's the same. The source of learning and authoritative reference is Malaysia, not Singapore.
Singapore has no language of its own. Malays were here first but they're the minority now. Chinese were here later but they're the majority now. The British had come and gone and left behind the English language in commerce and laws. The Indians are caught in between neither here nor there. But bear in mind, even Malays and Indians have to take their exams in English. You want them to take their exams in Chinese? Or you want to divide up the education system into four language mainstreams system?
You're just unhappy or even disgusted with your fellow Chinese speaking English more often. These are their personal beliefs, choices and problems, nothing to do with you or me. They may end up failures or sell-outs, or successes and buy-ins. You have your personal problems, choices and beliefs too. Take care of yourself and people under your charge. If you want to speak Chinese at home, it's fine. If others want to speak English at home, what's your problem?
Singapore is not a custodian of any language, whether Asian or European.