See last paragraph, and sibling comment: not really needed (except for extreme cases like preserving the last of a species). Plus I have a job and hobbies already :) Moreover, it's still not a very sustainable solution: you can get all the locally grown seeds you want, if you sow them in unfit soil (pH/moist/minerals/...) and/or soil which is just too rich in nutritients it's still no use and they either won't grow at all or get overgrown by grasses/nettles/... Especially the nutritiens are a common problem can usually also be solved by proper management (which more often than not starts off simply by mowing 2-3 times a year and removing the cuttings).