Why not offer your 100k subscribers a second newsltter as subscription model ? Example Teal Swan she has a whopping 25k subscribers list (separated from her big big email list) who paying her monthly $79 retainer. She makes a few mnillion dollars every month from that low tier.
Offer your 100k subscribers a separate newsletter as subscription, based on your niche, like inlock mindset, life coaching or whatsoever your niche is about. When you have a good 40% open rate =40k people reading your email , then 8-10% will buy that newsletter subscription (must be target to your niche solve problems) that will be 3200-4k people paying you $100 month (example) you will make $400k every month ! That is a very scalable business model. Other services in high ticket price range, here you need to have weekly 1:1 sessiobns with your clients which can be exhausting, it's not very scalable as single entrepreneur, with that you can have max. of 40 clients every month.
Many entrepreneurs build up a huge stable newsletter business income.
Like Tim Ferriss too, he promotes affiliate products/ services I guess ?
Tiom Ferris a note: many people not know he was a new york times journalist for 12 years, then he wrote a book. But he has good access to top connections in the medie/journalist world, his "friends" connections made him and his book famous, they spread out the word for him. You and I we not have these connections. This is often, what "famous" people like Tim Ferriss and others not tell you ! Welcome to slave planet earth - that make sense....think about it.
Happy Friday !