Indeed, the fact that IA was mainly used by government officials to travel between the dominions, and not run as a commercially viable passenger service, tells us something of its perceived importance to the 1930s Empire and its Government.
From our positions inside the aviation world we have to advise that quite a lot of what appears to be "commercial" aviation even nowadays is sustained by the government. Routes such as London to Washington, or even more (apparently) the Swiss daily flight between Geneva and New York which carries many UN staff, receive their revenue from government offices. as do, in varying proportions, a considerable number of other routes as well. Even the supposedly "business" airport at London City, not that far from Westminster of course, sees notable numbers of MPs and senior civil servants going through it.
It was true that in former times, with air services and even developments of aircraft types heavily supported by government, they tended to think they were the only people who justified travel by air. Some of the immediate post-WW2 British designs for long-haul aircraft had surprisingly low passenger capacity, down to a dozen or so, and reading the reports of the time it seems that only government officials were thought worthy of travelling on such services.