Corruption plays a significant role in how (un)attractive a country is to skilled workers. Rather than focusing on education or immigration policies, governments ought first to tackle corruption in the labour market if they want to attract international talent.
Ariu, A., & Squicciarini, M. P. (2013). The Balance of Brains: Corruption and High-Skilled Migration. EMBO Reports, 14(6), 502-504. https://doi.org/10.1038/embor.2013.59 (Original work published 2013)