The reason why single pilot ops won’t be around for the foreseeable future is incapacitation. Whilst increased use of automation may make a single pilot airliner a reasonable prospect you then have to make it fully automated in case of that pilot being incapacitated. So you basically need a far greater level of automation nearing AI level. And the bigger problem, you’ll also need uninterrupted and perfectly reliable ground to air communication in case of that incapacitation. There’s enough problems with VHF comms interruptions to prevent that from happening without a massive overhaul of the worldwide communications network.
Basically a minimum of 30 years before the first scheduled single pilot flight happens. Every single aircraft manufacturers are planning is two crew, and they’ll be in operation for at least 25-30 years.