It's sorta amusing to watch virtually every commentator on these policies not double-check what the previously existing policy setup was. There already are
tax incentives for extra kids, and there already are
subsidised housing allowances. This is just ramping up policies that were probably having an effect at the margin, but clearly haven't fixed the problem (if the OP's alarmist language were anything to go by).
And I reckon Orban and Fidesz's insistence on traditionalist roles for women are sabotaging this policy anyway. In the 21st century, women have choice about what they want to do with their lives. That includes forms of self-actualisation that weren't really considered appropriate fifty years ago - in work, hobbies, interests and behaviours. If you make having kids conditional on not being able to follow these other options, then some proportion of women who might have had a family will choose not to have it.
I reckon there's a U-shaped curve when you plot birthrates against some hypothetical measure of the 'conservativeness' of social expectations about what constitutes a good mother. If society is so conservative that choosing not to become a traditional mother carries a real threat of being ostracised, women are either forced to or educated to become just that (e.g. Egypt, rural Turkey, rural southern US, all to varying degrees). But if there's enough liberty and economic development to allow women to choose the live they want for themselves, but enough conservatism to see them (and their kids) judged harshly (by others and themselves!) for being a working mother with a live outside her kids, then you get dropping birthrates (e.g. Spain, Italy, Japan, Korea ... and Hungary). Once women are free to choose to have a family
and a life
and that is accepted by society, then the trade-off gradually disappears and birthrates should be higher again (e.g. France, Sweden or Norway). I think that's a big part of why in these latter countries, when you look at a time series birthrates have increased from the low-points they saw a couple of decades ago, while in the former they have not.
By that logic, if you want a higher birthrate you want the state to provide incentives that ensure the availability and use of infrastructure and services that make it easier for working women to also have families
and for the government to do what it can to legitimise working mothers in terms of society's expectations. That's what they do in France and Scandinavia, and it seems to be working. And, if I'm not wrong, Orban's emphasis on the 'traditional family' is sending precisely the opposite message to the one he should be sending if kids were his priority. They aren't, of course. Lots of kids are just part of the idealised 1930s world he wants to live in - lots of housewives is just as important. And so he dampens the impact of the taxpayer money he's blowing on this.