Because its a decision made by someone who clearly has no idea how modern web traffic works. That pricing model looks fine in a world where scrapers and proxies don’t exist. But in our world, they do exist, and small time devs will happily pay $5 for a handful of proxies and scrape the data they want from Twitter directly. You can’t really block them either, especially if they’re indeed small time devs who are just scraping casually.
These devs using scraping tools are loading up entire profiles and tweets, which consumes far more resources than a simple API call that gives them the precise information they want.
Cheap APIs discourage scraping and are most cost effective if you work out the tiers and rate limits.
And my point is that they don't care about the $5/month devs. And the scrapers or intermediaries will just expend their own resources. With less overhead on Twitter's backend.
It's pretty easy to throttle browser requests without anyone noticing and blocking excess requests from a single IP block.
That you think they should care, doesn't mean they actually do.
These devs using scraping tools are loading up entire profiles and tweets, which consumes far more resources than a simple API call that gives them the precise information they want.
Cheap APIs discourage scraping and are most cost effective if you work out the tiers and rate limits.