MIT still requires the license and copyright notice to be maintained though, it is why even proprietary software includes an 'open-source licenses' listing somewhere under help / alongside the distribution. Arguably, AI models reproducing a bit of MIT licensed code would be just as much in violation as with any other license.
GPL still gives much better guarantees w.r.t. providing the source code and modifications made thereto, though.
Most LLM chatbots don't push back when they should. When combined with situations like these, at a large scale, even 5 percent is abysmal, let alone 55 percent.