「車が開発されても、水素の供給インフラが整備するまでにまだたくさんの年月が必要です。」という一文を英訳するなら、

Even the vehicle has been developed, many years would be required for completing hydrogen supply infrastructure.

よりも、

Even after such a vehicle has been developed, many years will still be required for completion of the infrastructure that is essential for the supply of hydrogen.

の方が適切です。