Platforms and Marketplaces have one particular issue. You can build an awesome tool, make it robust, responsive, and even fun to use. You can put all the servers and routers behind it, and pour hours of development into it, but the real outcome gets determined by others.
The users, those providing the content, are who decide “what is it for?” and can range from welcoming positive support, to toxic, hateful trolls.
You have the option to push the boundaries of the “user agreement” and set rules that will change the tone, but at that point, you cease to really be a platform.
And with algorithms, and the social nature of platforms, the way anybody experiences them, is highly dependent on their connections, and their previous usage patterns.
Take for example Twitter. Is easy to use, robust, rarely drops, and it is simple. However, the experience that many people have is one of hatred and gloom.