Capitalism requires annual growth to survive. Typically, the annual growth in profits is considered to be acceptable if it is between 2 and 3 percent. From 1950 through 2018 the average annual compounded rate of increase in corporate profits was 6.37% as can be seen by analyzing the data in a spreadsheet: https://fred.stlouisfed.org/series/CP/ The average Q4 profit in 1950 was $31.581 billion, and in Q3 of 2018 it was $1,980.217 billion. That is 68 years of data. And that average 6.37% growth was achieved during an average inflationary rate of about 3%. Now let's take a small recent part of that time frame to examine. From 2012 to 2018 average corporate profits went from $1.97 trillion to $2.3 trillion in 6 years. That is an average annual compounded rate of increase of 2.8%. And it was at a time in which the stock market seemed unstoppable, and during an average inflationary rate of about 1.5%. Yet the former rate of growth was not achievable in any of those 6 years. https://www.statista.com/statistics/222127/quarterly-corporate-profits-in-the-us/ Compounded growth is not sustainable. If you create a spreadsheet representing 200 years of 3% compounded growth, you will see visually why it is not sustainable. The slope begins increasing gradually enough, but by the time it gets to 180 - 200 years out, the slope increases wildly to it eventually being nearly straight upward. And I assert that the problem capitalism is facing today is exactly what I've shown. The needed rate of growth cannot be sustained and it is not being sustained, and that is creating a very serious crisis for capitalism. It is likely to become an increasingly bumpy ride from here.
It's never going to happen, and it never needs to either. All capitalism needs is a few drops of quasi-socialist "hot sauce" to take it back to the days in the New Deal Era when our yankee ingenuity harnessed it as a tool to serve working families. Capitalism can be fixed, it has been in the past and it can be in the future, if we have the political will to do so without bogging ourselves down in hysteria and knee jerk reactionary dogma.
Capitalism has worked for over 300 years. Socialism has failed in virtually every society starting with the Greeks and Rome empire and all current socialist Governments. There is no way that the Government can pay for all the Programs Socialists want. It will be the middle class and self employed and small businesses that will pay the bill.
Sustainability is a big issue. However, whinge about capitalism needing growth to survive misses the point somewhat. Rather than Marx, you have to refer to the likes of the bio-economists...
Socialism has been trying to get established for about 100 years. That is about how long capitalism took to get going. Socialism wasn't attempted in the Greek and Roman empires. And your criticism is based on failed models that have been largely rejected by socialists. Your mention of capitalism having worked for 300 years validates what I said in the OP. It is unsustainable. You cannot sustain what is unsustainable once it becomes a problem to sustain it.
You talked a lot about compound growth but never actually showed that how capitalism will fail with just linear growth rather than compound growth. Most civilizations had a lot of capitalism going on, and had long periods of stagnation, but their capitalism survived.
Capitalism has never experienced linear growth for very long. The history, as I showed, has been one of compounded growth.
Certainly there are ups and downs but if you put the numbers I gave into a spreadsheet you'll see that the growth is equivalent to an average annual compounded rate of growth as I indicated. You are worrying about the ups and downs, but I dealt with the overall and averaged it. And that is the only meaningful way it can be done.
I'd argue that Rome fell because of foreign invasion. Rome had a massive number of slaves and trampled on its poor rather than gave them free stuff. Socialism didn't arise until the 20th century.
A welfare state is not socialism! That is a right wing distortion. Socialism is ONLY a socioeconomic system in which the workers own and control the MoP. Rome didn't have socialism.
Capitalism cannot exist without growth. Always, most capitalists will work to out-do the competition, and to do that growth is essential for strength.