If citizens are allowed to develop their own living space, which will be the role of planners?

Recently I read Zef Hemel's book 'De toekomst van de stad'. This book inspired me to my newest blogpost (in Dutch). I discovered some pattern in the development of towns, depending from the power of the state and the degree of (un)equality in society. This brought me to the question which policy and which planners we need in the future.
By the way, the illustration below was painted by my father in 1957. It depicts the Stokstraat in Maastricht, before gentrification developed it into one of the fanciest (and expensive) European shopping streets.