I doubt a company would be willing to deliberately risk losing sales by testing a worse version. AB tests are great in theory, but in practice, to test the current slow system against a faster one, you have to do the optimization work which the test is supposed to justify. That’s why AB testing is often used for quick wins, pricing points or purchase flows, but rarely the big costly questions.
Surveys could be used to explain the bounce rate, but getting feedback from people who leave is one of the hardest the recruit well for. Usability tests could help with that though.
