The warranty period doesn't directly tell you the driver's expected lifespan — it tells you how long the supplier is contractually obligated to replace it if it fails. A well-designed driver with quality components can last 50,000+ hours (that's over 11 years at 12 hours/day). A driver from the same brand but built to a lower cost target might fail at 20,000 hours. Both could carry a 5-year warranty if the supplier is pricing in expected replacements.
What actually matters: the Tc rating (case temperature at which the lifetime is specified), the capacitor brand and temperature rating (Japanese capacitors at 105°C vs. Chinese capacitors at 85°C — this is the single biggest factor in driver longevity), and the surge protection rating. A driver with a 5-year warranty but 2 kV surge protection will fail faster in the real world than one with a 3-year warranty and 6 kV surge protection if your grid has voltage spikes.
This is why we specify driver model numbers, not just brand names, and provide Tc ratings in our quotations. See our LED lifetime article for why L70 and warranty are measuring different things.