[Limiting scope to western economies...]
The problem is that a purely innovative technological change is usually tiny and incremental. Most existing technology is more than good enough for most people most of the time.
The really important problems that hold back progress, or oppress people's lives, cannot be solved by a quick-fix startup.
There is bureaucratic bloat, regulatory capture, crony oligopolies, over-regulation, vested interests, rent seekers, oppression by crisis, cover-your-ass management, negative sum legal action, nimbyism, planning quagmires, hyperactive enviromental zealots, bad zoning laws, silent majorities, corruption, luddite unions, private equity rape & pillage, dysfunctional politics at every level, propaganda, people that fervently believe propaganda, arrogant elites, useful idiots, incompetence as a badge of honor, capture of education/media, unaccountable globalism, sociopaths in power, aspirational victimhood, hypocracy, too much debt, economic obfuscation, government intervention, lack of common sense, too much individuality, lack of community, family breakdown, sustained irrationality, consumerism, distortion of the property markey, printing money, government setting interest rates, too many laws, too much surveillance, too many taxes, executive orders, two-party systems, deep state, military-industrial complex, nanny state, poverty trap, atomization of society, drug addiction, opiate deaths, over-incarceration, prison-industrial complex, war on drugs, espionage, excessive copyright protection, intellectual propety theft, nepotism, extrovert dominance, urban decay, litter, noise pollution, light pollution, modern architecture, processed food, particulate pollution, crumbling infrastructure, advertising billboards, did I mention too much debt? ...
... profit over truth, efficiency over beauty, feelings over facts, posture over competence, cheap talk over real commitment, do-what-I-say over watch-what-I-do, abstraction over practicality, focus groups over philosophical coherence, partisanship over leadership, and championing failure over success.
More fundamentally, there is the doom loop of democracies voting themselves more printed money for social welfare, while distracted by hedonistic bread and voyeuristic digital circuses.
Startups can't fix that.
P.S. Except maybe, er, bitcoin :)