A preschool like ours will not be sustainable if the 30 hours funding comes in - we are in a building used for after school and early birds clubs, so can't extend our hours, we have waiting lists for places and would not physically be able to accommodate more children in a session, without overcrowding, there would also be staffing and ratio issues.
The 30 hours thing is fraught with difficulties which don't seem to have been considered, not least the fact that early years education seems to have been mixed up with childcare provision, to the detriment of both (IMHO)
However, I think some of the reasons are not about childcare, for the parents I am thinking of, they want their child to start school, with the other children that are starting school, and I think this might be true for a lot of parents.
Having a later starting school age for all children, with a proper foundation of preschool, early years provision, would be better for all children.