Its not practical as well as feasible to have a real time blockchain system. What I am getting by your real time is that there is no delay og 10 minutes within each block so the transaction can go on swiftly. This isn't possible because we need to set block interval to minimum for that lets imagine we keep it at 10 seconds then we will have a lot of orphan blocks or less utilised blocks which will ultimately waste resources and bring nothing to blockchain. So some time difference is required for transactions to accumulate. But yes some blockchains have relatively faster block intervals like ethereum but don't expect smart contracts to be real time.