Forget not being able to find/afford a nanny.
Look at the whole issue from a different angle fro a moment.
When I went through Hamble (in the 60's) we were all male and apart from the odd medical problem gave BOAC/BEA/BA thirty five years service. A reasonable return on the training costs I would suggest.
Now there is the option if you are not successful in getting sponsorship with BA to pay for your own training. The figure would seem to be in the region of £80.000., without a guarantee of a job at the end.
That would not seem to be the end of the matter even if you succeed in finding a job there is most certainly the type rating to be paid for (B737 roughly £15000)
I wonder if Jessica would have been asking for 75%, let alone 50% working if she had that sort of debt to clear. Mind you she is married to a Captain, the odd £80,000 would help.
Perhaps BA will just ask future applicants to pay for their own training. Perhaps the like of Jessica will not make it through the first interview in future.