Those aluminium versions are already quite easy to make. Material costs per piece are quite small so almost whole price comes from labor "costs".
Injection mold costs about 8000€, paypack time is not the problem. Its the lack of that money for everything. Payback is about when 160000 pieces is sold, but of course that depends on the selling and buying price which are still open.
If you want those aluminium versions for your car send me some PR and I will try to get a better price, you might suprice
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Price can be lower is you buy the used zipties yourself. At the moment I am using Panduit:
PLT3S-CO 292mm long or 11 1/2"
PRT1S-CO 122mm long or 4 7/8"