Reagan / Thatcher Economics discussion

Recently I have been reading about the stagflation of the 1970's and also listening to various economists on this issue. It seems that the postwar Keynesian policies as well as targeting unemployment, while very successful up until the 1970s, caused the labour markets to become too tight, and allowed for an inflation crisis to occur at the same time as a recession (which was seen as impossible beforehand). Then Reagan and Tatcher came along and shifted the economic policies of their countries away from targeting unemployment, and towards reducing inflation. They achieved this by privatization, deregulation, union crackdowns, globalizing the labour market, etc. These policies did reduce inflation, but they also lead to a whole other set of problems. Reagan/ Thatcherism has now basically morphed into neoliberalism, which is the current world order it seems. Now, as a traditional leftist, I am obviously not happy with the way things turned out; but as an economic illiterate, I also do not know what the alternative was to the stagflation crisis. Will Keynesian policies always inevitably lead to this problem? What are the solutions?