[dragontamer]

> They never really run out, but eventually you’ll stop running regular trains to an oil depot because your reservoir tanks take hours to fill.

Speed beacons + Speed Modules + Infinite Productivity gets you pretty far.

> Pumpjacks give less oil over time.

Back in 0.13, they dropped to 0.1 oil/second. Today, this minimum has been grossly buffed, greatly reducing the number of depleted pumpjacks you need in endgame. The output is also improved by infinite-productivity research, increasing their output the longer your megabase runs.

There's also Coal Liquefaction, which came a few years after 0.13. That also reduces the need to find new pumpjacks (and again: because coal mines use electric mines, its possible to automate mines with blueprints).

So Coal runs out, but is far easier + automatic to expand compared to oil. So you just turn your coal into oil products.