Content creators keeping content locked behind a pay wall has nothing to do with Patreon and has everything to do with the content creators.
I also prefer Patreon as a download platform. I’m a patient person and try out cc or mods when they’re available to the public. Once I notice that I always use a mod (a mod that receives constant updates) or find myself often download cc from a specific creator, I’ll support them through Patreon.
I don’t support content creators who don’t offer me a chance to try out their mods or cc and force me to pay for all of their content before I can use it.
Most of them work on custom content as a hobby and oftentimes it doesn’t work as intended, e.g. clipping issues or their work is downright sloppy. I don’t pay for that. Show me what you’ve got before I send you my money. If it works well, I’ll be a good customer.