Why do serverless builds take sooooo long?

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2025-11-25 13:52:45 [INFO] Layer 10/13 e44bce5f1cce 30.6% [######..............] 3.73 GB/12.19 GB @ 0.96 MB/s ETA 150m54s (40/131)
2025-11-25 13:52:47 [INFO] Overall 23.8% [#####...............] 3.73 GB/15.63 GB @ 0.96 MB/s ETA 212m13s
2025-11-25 13:52:52 [INFO] Overall 23.8% [#####...............] 3.73 GB/15.63 GB @ 0.96 MB/s ETA 212m29s
2025-11-25 13:52:57 [INFO] Overall 23.8% [#####...............] 3.73 GB/15.63 GB @ 0.95 MB/s ETA 212m45s
2025-11-25 13:53:02 [INFO] Overall 23.8% [#####...............] 3.73 GB/15.63 GB @ 0.95 MB/s ETA 213m1s
2025-11-25 13:53:07 [INFO] Overall 23.8% [#####...............] 3.73 GB/15.63 GB @ 0.95 MB/s ETA 213m17s
2025-11-25 13:53:12 [INFO] Overall 23.8% [#####...............] 3.73 GB/15.63 GB @ 0.95 MB/s ETA 213m32s