That would be part of it, more significant I would imagine is the effort involved in making the ships having the required elements for X4:
* transporter rooms
* compatible landing gear
* correct dimensional range for each size class
* cockpits with X4 seats and consoles
Currently ship modding tools are fairly limited (especially for things like animations) which just makes this even more difficult. A further factor is demand and whether or not ship modders want star citizen ships.

Now I understand the reason behind it. Thank you!