Was your grandfather a big shot in the government, did he had farm lands and enough livestock to start such a large family? I bet he did. Its easy for you to say so because you live in the west and from what you post I conclude that you got your degree, over 30, don't have kids and heavily invested in stock markets.
What stops you from starting a big family than?
I usually agree with your insight on social trends/values and global geo-politics but this time you went over the top with having kids without family planning.
My grandfather became richer as he had more kids but before it he was a very poor man, we know from the sunnah that these are means of someone's riziq being increased when they are a believer, the more kids he had, the wealthier he became. I have seen similar stories like these a thousand of times.
You see in matters such as these you really have two choices, you either follow the religious edict and have iman or you go with your own whims and desires (in this case not even your own but those from others you have been indoctrinated with)
I choose to go with the deen and this has served me very well, I had long periods of dreadful poverty and illnesses most on here never went through but looking back at that right now it's the greatest thing that happened to me so your argument of privilege holds no sway here.
Family planning as the term is used today is satanic in it's origin, it's the doctrine of planned parenthood whom specifically set up shop in black/immigrant neighbourhoods exclusively to push these ideas, it's a Malthusian concept that believes the world problems come from overpopulation, a doctrine exclusively pushed by white fascists ideologues because their own fertility rates were dropping, they are all part of masonic lodges and secret societies hence (satanic origin)
I plan to have as many kids as I possibly can not fearing poverty one bit and I am not 30 as you thought, there is no need to fear this because it's not in my control anyway, I could be a millionaire today have 10 kids then loose all that money in a single afternoon, it's part of having a lack of imaan to even think like this and even worse arrogantly believing that it's you that controls your own destiny, it's an utter lack of humility.
I could bring my children up in the most religious setting/environment and be the perfect example but the outcomes ultimately and solely belongs to Allah only whom has the ability to look at things in so many different perspectives that I can't in his ultimate wisdom, I will only be asked about the 'efforts' that I put in and will not be asked about the outcomes because it's not in my control.
The proof is in the pudding, virtually all of our great grand fathers had many children and if any of them took these satanic advice's of yours (oh we are poor thus can't afford children) you wouldn't be here today neither would we as a nation, you are essentially arguing for your own extermination ironically.
I know colleagues I work with especially bosses that are earning more then double worry day and night about their finances, suffering from high blood pressure and early onset of grey-hairs etc. our grandfathers didn't even have a fraction of their wealth but raised 100's of children, it's no surprises that people whom think like this are often punished with spinisterhood, infertility, desolateness, barrenness, depression and other mental/physical health issues. etc.