While consumer drives overall might not have a significantly higher failure rate than enterprise ones, I can think of a few differences:
a) consumer drives are nearly always 7200rpm for normal models, 5400rpm for green or laptop models which directly influences the number of small random disk operations that can be performed per second and the overall maximum throughput. Enterprise drives typically range from 18000rpm at the very high end to 7200rpm at the absolutely lowest end, with 10K rpm probably the most common for bulk storage and 15000rpm for data intensive settings.
b) Enterprise drives are usually available for multiple connection types (fiber/SAS/SATA) whereas consumer drives are nearly always SATA only.
c) For some drive vendors, SMART reporting is much more consistant for enterprise drives. Also, the number of extra sectors on the drive made available for bad blocks to ensure the full capacity of the drive and to remap defective sectors can be significantly higher.
d) The newest difference between enterprise and consumer drives is that some manufactures are intentionally disabling typical enterprise firmware features on the consumer models, drive commands that are helpful for hardware raid/etc.
e) Guarenteed repair warranties on enterprise drives are frequently at least 1-2yrs longer than consumer
f) More attention is usually given to the impact of constant drive usage in the design of enterprise drives than consumer. While the average failure rate for drives in a 2-3yr timeframe may not be that different, I wouldn't be surprised if usage patterns over 5-10yrs resulted in a significant divergence. It's not that unusual for enterprise storage systems with dozens to hundreds of drives being in operation for at least 5 years, and frequently 10 years.
Also, I'd be curious about temperature variation tolerence. The longer a drive survives, the more likely it is to be exposed at least at some point to a brief period when normal building a/c fails or the computer chassis fans/etc fail....Not a few datacenter drive replacements have been required after datacenters have had power blips that resulted in a/c going offline for 10-20 minutes. This may not be a big deal for modern consumer drives where usage is relatively minimal and the drive is at least partially in low power mode.