No. Most of the iPad lineup uses LCD displays which are relatively thick. The headphone jack only fits in old iPads, because of the large bezels. On newer iPads, the headphone jack would need to go under the display, making the entire device much thicker. With OLED, you don’t have this problem, but Apple either uses LCD or Mini-LED for iPads.
Just look at the inside any modern smartphone, it’s full of battery and other stuff, basically no empty space. The iPhone 7 was the first generation without a headphone jack, it still used the old case design though. Look at the iPhone X which was completely redesigned, it’s just marginally larger than the iPhone 6/6s/7/8 (they all use the same case design) but has a much larger battery. They went from 7.45Wh (1960mAh) on the iPhone 7 https://blogs-images.forbes.com/aarontilley/files/2016/09/inside-iphone-7-front-back-1200x801.png
By removing the headphone jack and saving space, everything can be laid out in a way that creates more room for a larger battery, many manufacturers do this.
They take up quite a lot of space (for a phone) that could otherwise be used for a larger battery. I’ll happily take a few hundred mAh of battery life over a headphone jack. I find bluetooth headphones much more comfortable to use anyway. But I understand that some people prefer wired headphones.