That is correct. Also, when you see, how much space was available. On Commodore, the Basic had to fit into 8k+ (together with the "Kernel" it had 16k of Rom and

That is correct. Also, when you see, how much space was available. On Commodore, the Basic had to fit into 8k+ (together with the "Kernel" it had 16k of Rom and the Kernel needed ~7k) -- so space was really scarce -- a bigger ROM would have made the computers more costly.