There is a huge difference between building a clone today on top of today's tools and commodity cloud platforms versus building it originally on what was around in 2006 and then having to constantly add features, change things, and then maintain 15 years worth of accumulated special edge cases forever without downtime.
Comparing to Instagram seems pretty unfair too as it's newer, it was even-more-featured-limited for a long time, is now part of a much larger behemoth and had much lower scale than today's twitter when it was acquired, and my guess would be that it's an easier scaling problem too (lower on post frequency, more read-heavy workload).
Comparing to Instagram seems pretty unfair too as it's newer, it was even-more-featured-limited for a long time, is now part of a much larger behemoth and had much lower scale than today's twitter when it was acquired, and my guess would be that it's an easier scaling problem too (lower on post frequency, more read-heavy workload).