Why you can't cash out of Bitcoin??? , Anybody has similar experiences

I found an interesting and informative read on internet about 'Why Bitcoin's price is purely fictional' and it is really tough to get money out of exchanges when you want it.

I am relatively newer to the coin business. It seems lucrative as of now. I haven't pulled my money back yet but I was curious if there really are issues as described by the author here:
https://davidgerard.co.uk/blockchain/2017/12/17/why-you-cant-cash-out-pt-1-why-bitcoins-price-is-largely-fictional/

Have any of you guys had issues like this before ?? Would you like to educate fellow community about your experiences and potential precautions that newer members can take ?