Hmm. I just looked this up and there are several places that say the nicotine isn't required for steeping.
It doesn't make any sense to me that nicotine is needed in order for flavourings to come out. Nicotine changes colour when it comes into contact with oxygen or light. That and the maillard reaction between amino acids and sugars is responsible for the colour change. But nicotine isn't needed for a maillard reaction. Just heat, moisture and time. Nicotine is usually a very light yellow/orange (specifically nic-b salts) and that intensifies when it's been exposed to light and oxygen and can even look brown.
Nicotine does degrade at certain temps. At 79c you will lose up to 10% of it. at 65c you'll lose up to 8% of it. That's not much and I'm fine with that.
There are plenty of vapers who don't use nicotine, such as many Australian vapers and they still steep their liquids.
Additionally, my Zeus Juice. I forgot to add nicotine to it until I realised I was vaping it (after a few weeks when it got nice) and still craved nicotine lol. That one most definitely steeped. At first it wasn't nice. I couldn't taste the advertised flavours and it was weak. Very weak. I did the hot water thing and left it out and then put it away for 2 weeks just thinking it was crap. I then thought I'd try it again and it was ten times better, so that one steeped without nicotine.
I know I'm not very experienced etc but I don't believe nicotine is needed to steep an eliquid and there are various sites out there that concur.
This is one of the companies that explains that nicotine isn't needed for steeping. It's also one of the ones (among many) that gives the warm bath method as a way for steeping.
Another one that says nicotine isn't needed for steeping & lists the warm bath method.
I think the important thing though is what works for you. The warm bath method which is listed as a steeping method on several vaping/liquid sites works for me. It's just that some flavours I got I don't like and I need to find some that I do like. I've been given plenty of recommendations to try here so I'll get some ordered.