The 'Full Member' nonsense was only introduced as a political tool anyways. Once the ICC put 'growing the game' on it's todo list, the powers to be wrote that in to ensure that they got to control sport no matter how popular it got.
I obviously am not asking for places where cricket got popular in the pre-historic times because of them being British colonies or very closely linked to British colonies. I somehow suspect that model is not going to work any more.
The only notable country which was not a colony and developed a cricket following was Afghanistan and they did so only when the country was torn in pieces and millions had to flood to Pakistan.
If you rule out 'people who know the game going to teach a local population' as a way of growing the sport, then yea, it's impossible to grow. What kind of nonsense logic is that? Every sport ever has spread via expats (sometimes colonizers) teaching the local population.
There are Zero countries where cricket has gotten popular because of any actual marketing.
A) This is just blatantly ignorant. Thailand women have played in the world cup (and should be playing in this one), while Japan U19 qualified for the U19 WC as well. Their teams were made up with players who learnt the game in their country. Nepal has a massive cricket fanbase, PNG is comprised of entirely local players, as are teams like Vanuatu and Uganda who are currently on World Cup pathways. Brazil has an entirely professional women's team setup now too, and there are top quality cricket facilities in places like Oman, Malaysia, UAE and Thailand. The sport has gained popularity in a ton of places outside the traditional nations. Bermuda has an entire weekend public holiday dedicated to celebrating an annual 2-Day cricket match between the two biggest clubs in the nation, which is broadcast live on TV and attended by thousands of fans (Google the Emancipation Day Cup Match). Cricket is good and likeable.
B) The ICC doesn't actually do any actual marketing. That's the problem. Their vision of growing the sport is limited to sending out Criiio kits to associate nation cricket boards and assigning a token amount of funding to run complicated pathway tournaments that barely have any information or coverage available on them. Even 'real' cricket fans have no ****ing idea what's going on, how do you expect non fans to learn anything? If the ICC actually cared about growing the sport, they'd host Test/ODIs/T20Is in emerging countries, have larger World Cups, assign fairer amounts of funding and
let teams play Test matches if they want to. Countries like Argentina have been playing and hosting FC cricket longer than Ireland or Afghanistan have, and even Hong Kong have been playing multiday cricket vs Shanghai/Malaysia/Singapore/Thailand since the early 1900s. This is not an alien concept. The only reason the sport isn't more popular is because it suits the ICC to keep it a elite club.