"If you are going to have kids and run a company, you all need to sleep." and then he introdued me to a sleep trainer/coach.
"No way, we are not sleep training" was my thought, but I quickly realized that there is a difference between sleep normalization and what we know as sleep training.
The sleep coach gave us a completely customized regime for 2 weeks. Once the baby is 6 months or so, you can start. (up until 6 months, I just slept with the kids in my arms every night. Oh my god I miss those nights now. It makes me cry to think about how wonderful it felt.)
We've done it 4 times now and all our children gladly sleep from 7pm to 6:30am every single night. (The older ones now go to sleep more like 9pm). Everyone in the house is rested every day and it makes a big difference. Those two weeks are a lot of work for one of the parents (it is specified that one person should be focused on it) but in our experience it works by the 3rd night or so.
The main takeaway from the aproach is to disassociate eating and interaction from the act of sleeping. It created buffers between feeding times and play times and when you finally put them down in their crib to sleep. If they do wake up during the night they don't think "oh, if I cry I will get to eat right away." and they self-soothe and go back to sleep. If they do wake up hungry, it's a failure of the parent to have ensured they've eaten properly. You adjust as they grow. (A hungry cry is totally different from a discomfort or bored cry. You learn them pretty quickly.)
When I put my 10 month old in his crib to sleep now he looks back at me briefly and then turns over and gets in his sleeping position and he's asleep before I leave the room. It's such a relief knowing that no matter how badly a day goes, you can sleep that night.
I've had a lot of friends think this isn't for them, but 100% of the ones I have convinced to do it (and in some cases have just paid for) have been successful.
I'll also add that 2 of our kids were "colicky" and were very unfcomfortable during the day for their first year. Even still we were able to have them sleeping the entire night most nights after 6 months.
Again, there is no "cry it out". In fact, the baby almost never cries at all in this process in my experience.