Startups, if successful, grow into bigger companies. But why do you think bigger tech(or non-tech) companies are not entangled in bureaucracy?
A government is far bigger and complex than any big company. So there will be more slowdown compared to big companies.
One example of successful public-private partnership is India's "Digital India" initiative where the government was able to churn out platforms like Aadhaar, Unified Payment Interface and RuPay, with other platforms on the way for digital commerce for MSMEs.