Could we replace the tired old world religions with another? I think there is enough evidence to suggest that a new one could never have the same features as the old ones. For a start, vastly improved education would prevent any repeat of a religion being based on signs and symbols, which was the language of the illiterate. Law and order would prevent the type of start up by the sword which was found in Islam. The global clampdown on harmful drugs would prevent religions like Hinduism, Buddhism and Christianity taking off. A need to see proof, as well as credibility would preclude another Mormon type religion.
The drugs and alcohol religions (Hinduism, Buddhism and Christianity) were based upon heightened states of consciousness achieved with these substances. Can we identify these stimulants? We can take a good guess at some. For Buddha, whose enlightenment under the Bodhi Tree was accompanied by a feeling of timelessness, the plant may have been the Soma or Haoma. Drinking it led to immortality. Its use was also described in the Vedas and in Zoroastrianism.
The mushroom Psilocybe Cubensis was the hallucinogenic mushroom which grew in cow dung and was probably the reason why cows were elevated to sacred status in Hinduism. Surely that could never happen again?
The Fly Agaric (Amanita Muscaria) was the likely magic mushroom used by the early Christians. This was eventually replaced by a reverence for wine and beer. Many medieval monasteries were little more than breweries. Buddhism did at least ban the drinking of wine in its 5 precepts, but it has not banned the use of hallucinatory drugs.
With Aleister Crowley who attempted a start up religion, heroin was used to attain a state of consciousness called Dhyana. Unfortunately for Crowley the Dangerous Drugs Act was then passed.
There couldn't really be another like Joseph Smith either. The public would demand proof of the existence of the Golden Tablets. Any religion with an element of the supernatural, which includes most of the above, would fail the credibility test.
In that case, could science be one day elevated to replace religion? I think its only a matter of time. The post human has already been glimpsed. A sort of part man / part machine which would have no need of the old beliefs.