Some countries in Africa are certainly "stuck" but Kenya is actually doing pretty well overall [1]. Per capita GDP is about where South Korea was in 1969, or India in 2018, and Kenya's economy has been growing pretty steadily since one-party rule ended circa 2002.
Economic reforms and cutting down bureaucracy are certainly part of the solution, but "just wait a bit longer" is too. If things continue progressing as they currently are, Nairobi will look a lot more like Seoul by mid-century.
[1] https://fred.stlouisfed.org/series/NYGDPPCAPKDKEN