The same country's second or third city routinely costs noticeably less to visit than its capital, for the same standard of hotel and meal. The gap comes from what drives demand in each place.
Capital demand is layered and constant
A capital receives government business, corporate headquarters travel, international conferences, diplomatic traffic and tourism, all at once and all year.
Those segments have different price sensitivities, and business travel in particular pays whatever the rate is because the trip is necessary and expensed.
Hotels therefore set rates against the least price-sensitive segment present, and leisure travellers pay a rate that was not calibrated for them.
Second cities have thinner weekday demand
Outside the capital, corporate travel is concentrated in specific industries and specific weeks rather than running continuously.
That leaves more nights where hotels are competing for whatever demand exists, and competition pushes rates down toward operating cost.
The pattern often inverts across the week: a business-oriented second city can be cheapest at weekends, when the capital is most expensive.
Land and wage costs are genuinely lower
Central capital real estate is among the most expensive in any country, and hotel room rates have to service the cost of the building they sit in.
Wages, particularly in hospitality, track the local cost of living, which is lower outside the primary city.
Restaurant pricing follows the same inputs, so the discount is not confined to accommodation but appears across the whole trip.
Supply is less constrained
Historic capital centres have limited developable land and strict conservation controls, which caps how much new accommodation can be added.
Second cities more often have available sites and lighter constraints, so supply responds to demand rather than lagging behind it indefinitely.
Short-term rental supply is also less saturated, which keeps that market competitive rather than concentrated in a few streets.
What the trade-off actually is
The saving is real but comes with fewer direct international flights, which can add a connection or a train leg to the journey.
Cultural institutions are usually smaller, though the major regional museums are frequently excellent and far less crowded than their capital equivalents.
Rail connections between a capital and its second city are often fast enough that basing in the cheaper one and day-tripping is a practical structure for a trip.