Good developers will also prefer to be well paid and have a good environment while working with modern toys instead of MUMPS infested codebase.
(This is not an argument in favor of running after every new technology immediately, but you'll have trouble hiring and keeping good development on a JavaEE 2 environment with SVN build system based on 1990 code practices.)
To most developers, interesting problems and technologies are part of the compensation. To attract talent to work for unattractive technology you'll need very attractive salary and benefits. If a developer can't expect to gain transferrable skills from a job, that must be factored in. Jobs where you gain experience nobody else needs are the start of many year-end careers.
OTOH, sexy startups often get away with paying less but, in return, offer environments a DAX-level customer simply can't.
(This is not an argument in favor of running after every new technology immediately, but you'll have trouble hiring and keeping good development on a JavaEE 2 environment with SVN build system based on 1990 code practices.)