As performance increases we'll to have worry about it less and we'll get the luxury of choosing more powerful abstractions. This makes us more productive (e.g. garbage collection - static typing too is partly compiler optimization).
Regardless of performance increases, sometimes more powerful abstractions appear anyway. e.g. the relational database, Amazon S3, the git filesystem.
Better abstractions are what makes us more productive, not methodologies.
Will we ever be able to create abstractions or systems of abstractions that make software development significantly (orders of magnitude) more productive than what we have now? And if so, will we ever reach the point where users/customers/clients can have very capable and sophisticated custom made or customized applications for a price that warrants "wasteful" or "trivial" (for trivial reasons) software development?
Regardless of performance increases, sometimes more powerful abstractions appear anyway. e.g. the relational database, Amazon S3, the git filesystem.
Better abstractions are what makes us more productive, not methodologies.