Yes, it is possible to hear a long way on a crystal set. The equipment needed can be extremely simple too. What is needed are a good pair of ears and sensitive headphones. My ears are getting old and if I can hear this DX then younger ears certainly can. I have found a low cost very high impedance crystal earpiece worked well. You may have better headphones?
Copying amateurs, most of whom use SSB, is more difficult. Remember, a simple crystal set is only able to envelope detect, although in the USA 75m AM signals are regularly copied at great range. Some SSB signals on 10m Es should be strong enough to envelope detect. Based on my tests, if stronger than 500uV to 1mV the signals should be copyable. Quite a few signals can be this strong.