Now now now, this is just a simple one-line response, yet even then i find there are multiple layers of things i find objectionable in it, i'll go at some length over them (forgive me for the long post that is to follow):
Most of us would consider the concept of "free market" to be an ideological abstraction - all economic relationships are embedded into political, social and cultural institutions (see Polanyi), a massive amount of deliberate State intervention is required in order for any sort of market-centered society to even exist at all. It takes a massive bureaucracy and police force in order for modern private property, contract law and money to even exist. As such, markets (and their relative "freedom") can't really be understood by the amount of "State intervention" they suffer but through what sort of institutions underpin them and what sort of State and social regulation they suffer, and when you understand that it seems to me that the term "free market" is only ever used to refer to a very specific form of market-driven society underpinned by a narrow and specific set of political-economic institutions and with a very narrow set of available economic policies rather than markets in general; and i find it very doubtful that this very very specific form of market-driven society is the only society that doesn't cause mass famine.
The idea that this very specific sort of market-society is the only alternative that doesn't lead to starvation is empirically wrong. I mean, for starters, there are plenty of literal hunter-gatherers who aren't constantly starving (contrary to what the conventional understanding of poverty would predict about them). And James C. Scott's The Moral Economy of the Peasant analyses in detail the workings of pre-modern, non-market-society agricultural societies in Southeastern Asia and also analyses in detail how the forceful introduction of those communities into the market-society caused social instability and famine (once traditional social safety nets were eroded and eliminated in order to make way for market relations). And leaving aside these two examples of non-market non-starving societies (which i believe you will probably simply dismiss due to their pre-modern character), the idea that there are no alternatives to the market-centered society that could at the very least provide basic survival to people is so far completely baseless and if anything only betrays a lack of political imagination. Why is the market-society the only a priori plausible alternative that doesn't lead to starving?
We usually don't consider "capitalism" to mean "free market" economy, capitalism is a specific sort of market-driven society characterized by the separation of society into classes of capitalists and proletarians and where the accumulation of monetary surplus is the chief imperative of production. There have been plenty of anti-capitalists who have been more or less in favor of different market arrangements. So even if you are right that a large role for markets in the economy is necessary in order to prevent starvation in a large and complex society like ours, this still does not imply that there is no alternative to capitalism, it just means that we should look for the viable alternatives in the set of market-socialist theories.
Now, i'm sure you believe there are more market failures that merit social regulation of markets than just negative externalities; but do you believe the only problem of externalities and market failures is that they "reduce growth"? Or, more precisely, do you think the central priority of an economy is "growth"? I mean, say, stopping certain externalities like carbon emissions usually slows growth but it's necessary if we want to protect life on the planet. I would also argue that an economy beyond providing basic sustenance and a healthy amount of material comfort should also provide stability and participatory, deliberative spaces where people can build an active community - is more growth really worth it if it requires the dissolution of communities, an increase in cut-throat competition and instability that leaves people anxious and stressed out all the time, and a generally alienated lifestyle? Beyond a certain level of affluence, is growth really the priority here? And when the distribution of income is extremely unequal, do the people at the bottom of the social hierarchy have any reason to prioritize growth over redistribution?