Apart from accidental damages, poor maintenance is one of the main reasons for tyre failures.
Tubeless tyres and valves are not completely airtight. They lose air naturally, as the air molecules pass slowly through the body of the tyre and valve, gradually reducing the air pressure.
When running underinflated, the sidewall of the tyre is over flexing causing undue strain on the casing of the tyre. Also, the over flexing causes the bead to rock over the rim flange/horn wearing the bead, and also allowing foreign matter to enter into the interface between tyre and wheel. A pressure maintenance schedule is vital to achieve a full tyre service life.