> they can't be expected to provide free or low-cost apis across the board forever
They _could_ if it supported people building stuff that increased engagement so they could sell more ads.
I think it's mistaken to think of free-to-access APIs as something the company 'gives' to users at some cost to itself. Done well, it facilitates making the platform a richer place, where people spend more time and attention, and which is therefore more valuable. It's hard to do the attribution to definitely say k% of timeline views (and thus ad impressions) wouldn't have happened without API-dependent stuff, but that doesn't mean it's 0%.
Some categories of examples of stuff that I think formerly contributed to engagement but which would just not get built today:
- write only twitter-bots which give information on e.g. earthquakes, public transit delays, in a way which is genuinely informative, and does not enrich the author(s).
- interactive twitter bots which made twitter itself better to use. The most important in this category may have been Threader, which was ultimately acquired by twitter. But it would have been useless / never written under the new rules. Can you imagine trying to call it, and receiving no reply b/c it had exceeded its limit for the day?
- interactive twitter bots which made twitter a platform from which to do other stuff. E.g. your.flowingdata.com was a self-tracking project where you recorded information by tweeting. Treating twitter as a platform, and orienting itself around tracking routine stuff meant that using this project _required_ you to frequently engage with twitter. This was also a free offering, which wouldn't have existed under the current limits.
An ecosystem in which there are high costs to building means less stuff will be built, and the platform overall is less interesting, less compelling, less worth scrolling through an ad to see. Thinking of these APIs as just a cost center is misguided.