That's a strange reading of Agile to me. Agile is not about making developers fungible, it's about building high performing teams of people. That takes time, and it is set back any time you have to replace someone. There's plenty of Agile literature that points out the hit to velocity when there's turnover.
As for 'i can get something in 2 weeks rather than waiting for 2 years', that's about not waiting 2 years to find out that you've been building the wrong thing or that the software sucks. Maybe as you deliver features you'll find out that the application is good enough in 18 months. Maybe you'll find out after several months of sprints that the product owner is bad at getting requirements and you need to do something different. Or maybe you'll find out that it is taking longer than original estimated to deliver functionality so important dates need to be adjusted accordingly.
In the old waterfall model, all that bad news may not come out until 2 years later when the software is released. And in the old model the customer is not getting useful software until 2 years out, rather than much sooner with a minimally viable product.
Agile is not a panacea and any methodology will fail if attempted by dysfunctional/incompetent groups of people. But if there's one benefit of Agile, is that everyone should find out much sooner that things are going awry.
I've worked in waterfall and agile for 15 years, and the key lesson from Scrum is that it effectively exposes bad news early on. The scrum ceremonies do just that and nothing more. Once you get the bad news open and dealt with a lot of other work is made more worthwhile.
As for 'i can get something in 2 weeks rather than waiting for 2 years', that's about not waiting 2 years to find out that you've been building the wrong thing or that the software sucks. Maybe as you deliver features you'll find out that the application is good enough in 18 months. Maybe you'll find out after several months of sprints that the product owner is bad at getting requirements and you need to do something different. Or maybe you'll find out that it is taking longer than original estimated to deliver functionality so important dates need to be adjusted accordingly.
In the old waterfall model, all that bad news may not come out until 2 years later when the software is released. And in the old model the customer is not getting useful software until 2 years out, rather than much sooner with a minimally viable product.
Agile is not a panacea and any methodology will fail if attempted by dysfunctional/incompetent groups of people. But if there's one benefit of Agile, is that everyone should find out much sooner that things are going awry.