A little humble opinion, just a little. First of all, it must be related to the marketing strategy of software companies. Secondly, as far as I know, bocad is very powerful, but judging from the usage habits of domestic users, it is slightly less easy to use than tekla, or tekla is easier to learn, which is also one of the reasons. Furthermore, it may be related to the industry that your software values. Tekla may mainly focus on building steel structures, at least in domestic applications. bocad is said to be widely used in marine engineering at present.