Lights aren’t exactly cheap either way; even years ago they would be about $100 a pole just for the light, modern LED ones are about that [1] and cities can have thousands of them [2]. For example, the 250,000 lights in NYC at $125 per light (without even considering installation) would get you about $30M.
[1] https://www.edn.com/weighing-the-costs-of-led-street-lights/
[2] https://www1.nyc.gov/html/dot/html/infrastructure/streetligh...