I don't think so. For many companies, it's better to sell to a smaller market with higher profit margins (e.g. SaaS web apps) than to sell to everyone and lose

I don't think so. For many companies, it's better to sell to a smaller market with higher profit margins (e.g. SaaS web apps) than to sell to everyone and lose money (e.g. paying the iOS tax). And those 30% are surely large enough to completely eat up profit margins in some markets.