Correct. Only publishing houses have the ISBN given by the state. If you want to get ISBN, you have to set up a publishing house.

However, the nature of cultural communication companies is different from that of publishing houses. At present, most publishing houses are public institutions (a few are also state-owned enterprises), while many cultural communication companies are private enterprises.

If you want to publish a book for yourself, you can find a publishing house. Your manuscript is of high quality, and you can publish it without spending money. If it's a big deal, you can publish a book at your own expense.

If you want to get the book number and sell it to others for publishing, it is forbidden according to national laws and regulations. ISBN can't be bought or sold, and the publishing house of your position is afraid to sell it to you.