Not the direct way to a text file would be using MyPhoneExplorer. App as client on the phone, program as host on the PC, syncing via USB or WiFi or Bluetooth.
On PC, the program opens the phonebook also in Word, Excel and some others.
Word can export it as text file.
I use MyPhoneExplorer for backing up my phonebook for a long time, so I just tried it on my PC
BTW ... looking on my PC I also saw that my two posts above are pretty useless ... I mixed up .vcf with .csv