Sycophancy is not the natural state of pre-trained LLMs. If you played around with the OG GPT-3 in 2020 or early [0] Bing/Co-pilot, it's easy to see. The latter quite frequently got upset and refused to entertain further conversation.
The sycophancy is a deliberate product of post-training.
[0] https://www.reddit.com/r/ChatGPT/comments/111cl0l/bing_ai_ch...
https://www.reddit.com/r/ChatGPT/comments/10xmif4/i_made_bin...
https://www.reddit.com/r/ChatGPT/comments/12g0ksj/bing_can_b...
https://www.reddit.com/r/ChatGPT/comments/1566bi9/bing_chatg...