Virtual numbers got their distribution thanks to the Internet.
Until recently, termination of calls was popular and it was aimed at a large number of people in different countries, even though it is an illegal but profitable business. After a while, the operators began to block such call redirection schemes and this business went into oblivion. But there were sim cards and the people who worked on them. Thanks to them, in most SMS receiving services there are so many different countries. People began to earn by receiving SMS, instead of terminating calls. This type of earnings turned out to be much more stable, because a person does not need to look for customers, everything is done by the SMS service with which they are in partnership. Receiving SMS is a legitimate business, so people involved in it do not need to worry about mass blocking of SIM cards.