what is it called when people or businesses move to an area to invest money in housing and services, which in turn creates more jobs and attracts more people?

Gentrification.

Explanation:

Gentrification is the renewal and rebuilding of the urban environment, which takes place when wealthier middle-class people move to declining areas, displacing the lower-class people there. As a result of gentrification, the average family income in the community increases and the number of members decreases. This is believed to be due to the departure of poorer residents who are unable to pay the increased rent and other real estate and land taxes. Old industrial buildings are often converted into dwellings and shops. In addition, new stores and service facilities are moving to the area, serving a wider customer base. This in turn increases the attractiveness of the region for more affluent immigrants and reduces accessibility for the poorer.  This process is often made possible by government-funded investments to improve local infrastructure, mortgages for poor and first-time home buyers, and financial bonuses for owners of dilapidated houses. Following the implementation of these economic measures, crime in the area tends to decrease and real estate prices and tax revenues rise.