Yea, it starts from the nearest people to the site before it will begin to spread and eventually gets adopted by many people. The challenges of breaking through and being trusted is why new gambling sites need to engage in aggressive advertisements in social media and forums like here by running signature campaign and also have good welcome bonuses to attract new gamblers and then have a working and trusted system to keep them.
Yeah. For every new gambling site, gaining the trust of customers is of the utmost importance. While the industry is growing, there is no way for you to ensure that the user will give your site a try and actually consider your site as a trustworthy brand to place their hard-earned money on. That is why they need a well-executed marketing strategy and reliable back-end that will never have their customers getting disappointed and giving up on the site. To optimize site's conversion rate, one can look at plenty of different strategies for enhancing customers' experience.
Every new site will sometime become old and trusted, just that some few ones try many shady deals with trying to survive their early stage.
I wouldn't say that every new site will eventually become old and trustworthy. That's an optimistic assumption. There's a lot of competition in the market and not every new site will survive.