A revolution is a fundamental and often rapid change in the political, economic, and social structures of a society, typically involving a significant degree of popular mobilization and often violence. The extent to which a revolution replaces the existing order is a complex question, as outcomes vary widely depending on the specific historical context, ideology, and forces involved.

High Extent of Replacement (Radical Transformation): Revolutions can indeed lead to a near-complete overhaul of the existing order, particularly in the following aspects:

1. Political System: This is often the most immediate and visible change. Revolutions typically overthrow the old regime (e.g., monarchy, colonial rule, authoritarian government) and replace it with a new form of governance (e.g., republic, communist state, democracy). Examples include the French Revolution (absolute monarchy to republic), the Russian Revolution (Tsarist autocracy to Soviet communism), and the Chinese Revolution (imperial rule to a communist state).

2. Economic System: Many revolutions aim to fundamentally alter economic structures. The Russian and Chinese revolutions, for instance, replaced feudal and nascent capitalist systems with centrally planned socialist economies, involving land redistribution, nationalization of industries, and collectivization.

3. Social Hierarchy and Class Structure: Revolutions often seek to dismantle old social hierarchies based on birth, wealth, or privilege. The French Revolution abolished the aristocracy, while communist revolutions aimed to eliminate class distinctions and empower the proletariat and peasantry. This can lead to significant shifts in power dynamics and social mobility.

4. Ideology and Culture: Revolutionary regimes often impose new dominant ideologies, symbols, and cultural norms. This can involve rewriting history, changing educational curricula, promoting new national narratives, and even altering daily life practices to align with revolutionary ideals.

Partial Replacement and Enduring Continuities (Moderate Extent): Despite radical aims, revolutions rarely achieve a total replacement of all societal elements. Several aspects often persist or re-emerge:

1. Deep-Seated Cultural Norms and Values: While political and economic systems can be transformed, deeply ingrained cultural practices, religious beliefs, family structures, and informal social norms often prove highly resilient. These aspects may adapt or go underground but rarely disappear entirely.

2. Bureaucracy and State Apparatus: Even after a revolution, elements of the old state bureaucracy, administrative structures, or military personnel might be co-opted, adapted, or simply continue to function, providing a degree of continuity in governance.

3. Economic Realities and Inequalities: While economic systems change, underlying economic challenges, resource distribution issues, or new forms of inequality can emerge. For example, state control in communist systems sometimes led to new forms of privilege and inefficiency.

4. Unintended Consequences: Revolutions often have unforeseen outcomes. The initial revolutionary ideals may be compromised, leading to new forms of authoritarianism, internal conflicts, or a failure to fully achieve the promised utopian society.

In conclusion, revolutions are powerful agents of change that can fundamentally replace political and economic orders and significantly alter social structures and ideologies. However, they rarely achieve a complete tabula rasa, with deep-seated cultural elements and practical realities often ensuring some degree of continuity or the emergence of new, unanticipated forms of social organization. The extent of replacement is thus significant but seldom absolute.