I think there's definitely an element of "use it or lose it" with batteries. I may be tempting fate but I haven't had to buy a new battery for a modern bike in decades. The last time I did was in the early 00's for a Guzzi Le Mans. Since then I must have covered over 200k miles on 2 other Guzzis, 3 Triumphs, a KTM & a BMW. All have been on their original OEM batteries all the time I owned them.
When/if they were not being ridden regularly they were connected to a Optimate charger for maintenance/trickle charging.