From the perspective of someone who frequents Hacker News then of course it's going to seem like there's a ton of sites using the nearly-stock bootstrap look. That's because people like us actually look at sites like "Built With Bootstrap" and check out people's demos of bootstrap sites. Back in the real world the average internet user will likely never notice.
Most sites in the early stages will have few visitors and due to variety of interests it's unlikely that a single person will be using a large enough number of these sites to start realizing this problem.
As the successful sites grow larger and move beyond the early stages it's likely the developers will have access to more resources to improve their site theme over time and move away from the bootstrap look.
Most sites in the early stages will have few visitors and due to variety of interests it's unlikely that a single person will be using a large enough number of these sites to start realizing this problem.
As the successful sites grow larger and move beyond the early stages it's likely the developers will have access to more resources to improve their site theme over time and move away from the bootstrap look.