A pair of boots worn regularly can last a decade, while sneakers worn the same way are finished in a year or two. The gap comes from where each design fails, not from how hard they are used.
Foam midsoles die from compression
The cushioning in most sneakers is a moulded foam containing gas-filled cells. Each footfall compresses those cells, and they recover slightly less each time.
After a few hundred kilometres the foam has permanently lost a portion of its original height and rebound, which is felt as flatness underfoot.
Nothing about this shows on the outside. A sneaker can look almost new while the component that defines its function has quietly stopped doing its job.
Boots put the wear on replaceable parts
A traditional boot has a leather or rubber outsole, a stacked heel and a leather insole that moulds to the foot. The parts that wear are on the outside.
Outsoles and heel blocks are consumable and designed to be replaced, and the stitching that attaches them can be cut and redone without touching the upper.
The result is a shoe where the expensive component, the upper, is protected by cheap parts that get renewed several times across its life.
Leather improves under maintenance
Full-grain leather has an intact fibre surface and responds to conditioning by staying supple. Cracking comes from drying out rather than from age itself.
Synthetic uppers and coated leathers cannot be fed the same way. Once the surface layer cracks, the damage is structural and spreads with each flex.
Which means a boot rewards maintenance while a sneaker mostly does not, and the difference compounds over years rather than showing up immediately.
Construction tolerates rebuilding
Welted and stitchdown boots are assembled so they can be taken apart. The insole rib and welt survive multiple resoles before they need replacing themselves.
Cemented sneakers are bonded permanently, and the bonded edge is usually the first place a repair attempt destroys the upper.
The choice between these methods happens at design stage, and it fixes the maximum life of the shoe long before it reaches a shop.
Use patterns differ as well
Sneakers absorb repeated impact loads that fatigue foam and stress bonded seams. Boots are usually worn for walking and standing rather than running.
Boots are also heavier and stiffer, which means less flexing per step, and flex cycles are what eventually open glue lines and crease uppers.
A fair comparison therefore is not boots against sneakers but a repairable shoe used moderately against a bonded shoe used hard, which explains most of the gap.