as a customer, i don't have the choice to not pay for such upgrades but continue using the old one.
It's the same with hardware. At one company we used to operate a 3-year hardware refresh cycle and this used to make a lot of sense, 3 years was a long time in hardware, and this assumption was true for a long time. But the pace slowed as manufacturers stopped making big improvements and just started eking out marginal gains. We looked at our kit and our workloads and realised that we had plenty of capacity and instead of refreshing proactively we should stretch it out to a 5 year or longer cycle and replace failed equipment with new rather than disposing of things that still worked perfectly well after 3 years. Saved a ton of money doing this, both in buying hardware and in the effort taken to move applications around. Of course manufacturers got wise to this and looked for ways to get you back on that treadmill.
Yes, but I think that misses the original point of OP's argument, which is that the variable cost nature of SaaS is beneficial to customers that don't want to or can't think about 3 vs 5 year lifecycles.
And while you may still have a perfectly valid use case for hardware, I think the growth of IaaS speaks for itself in showing that variable pricing is popular.
It's the same with hardware. At one company we used to operate a 3-year hardware refresh cycle and this used to make a lot of sense, 3 years was a long time in hardware, and this assumption was true for a long time. But the pace slowed as manufacturers stopped making big improvements and just started eking out marginal gains. We looked at our kit and our workloads and realised that we had plenty of capacity and instead of refreshing proactively we should stretch it out to a 5 year or longer cycle and replace failed equipment with new rather than disposing of things that still worked perfectly well after 3 years. Saved a ton of money doing this, both in buying hardware and in the effort taken to move applications around. Of course manufacturers got wise to this and looked for ways to get you back on that treadmill.