The problem with banning contraceptives is that you don't actually need modern contraceptives to crater the birth rate. The first country in the world to undergo a major demographic transition was France, and they did it in the 19th century, which is obviously long before modern contraceptives, the pill, modern condoms, legalized abortion, IUD etc. Yes, the pill makes things really convenient, but French peasants in the 19th century were able to figure out how to control their fertility. Romania tried banning contraceptives, and the birth rate rose markedly at first and then went back down to the baseline.
Ideas about paying money have generally not worked either, they've been tried by a variety of countries. Generally you get an initial boost and then things settle back to normal. The most recent one was Hungary which passed some ambitious pro-natalist packages a few years ago, particularly focusing on things like housing, and you can check the results for TFR easily enough - it went up by something like .1, from 1.45 TFR to 1.55. Lots of countries have had cash bonuses to mothers for births and it's useless. This is pretty logical - yes people today will talk about it is financial burdens which are preventing them from having kids, but their ancestors pumped out a dozen kids in grinding poverty which is utterly alien to contemporary society. France has a lot of programs that support fertility and their birth rate is something like 1.9, which is better, although it is partially due to higher fertility among immigrant populations - not completely, I think I remember that among native-borth cohorts it is something like 1.7, which is still higher, but in any case neither of those numbers is above replacement rate figures and so doesn't really classify as a baby boom to my eyes.
The bigger issue is why people should have kids, since children, other than emotional support, provide no real benefits. Children previously were relatively low cost, the time to take care of them was limited, you had a bushel of them so they took care of and watched over each other, in the countryside they would be contributing light labor within a few years, in the cities would often be apprenticed off, and they provided the only real system of retirement. Nowadays, you have to take care of children for at least 18 years, and even if you make them work as early as possible at least 15 or 16 years of complete support, expenses like healthcare, housing, childcare etc. have exploded, and for a lot of parents who send their kids on to college it's probably something like 25 years of taking care of them and education will cost a huge amount. Plus now there are retirement systems, and Americans tend to just dump their parents into retirement homes anyway.
Events like the post-war baby boom can be better thought of in terms of a demographic correction , since the previous 30 years in the Western world had been a time of such stagnant demography, with major losses in wars and depressed fertility throughout the Interwar. In this sense, there was no baby boom, just a catch-up after years of stagnation. Similarly, you can see how in Europe the two countries with the highest fertility are France and Ireland, who had the worst demographic experiences of the 19th centuries. A similar baby boom might happen in the context of another period of major growth and expansion after a period of doldrums and war.
If you want a baby boom without this, simply people tomorrow deciding to have far more children, you would need a change in social attitudes. I wouldn't be surprised if this happens eventually, the unprecedented thing with modern contraceptives is that it is an individual choice, as compared to pre-modern fertility control which was exercised via social control such as infanticide, economic constraints over marriage, delay of birth, excess population to convents, etc. while nowadays women decide themselves whether they want children or not and control how many they have. Eventually this will self-select for population groups and to a more limited extend individuals with more children, as you can see with the Amish or the Dutch Bible Belt.
But in any case, future demographics are extremely hard to predict. People in the Interwar were talking about the demographic extinction of Europe and North America, and then a few decades later there was a major baby boom. As mentioned, there are major scientific developments in the tubes (pun?) which could change everything, although of course they could flop as well.