Is zakat obligatory on the value of commercial shops that their owner does not wish to sell, a portion of whose capital (one million Riyals) was allocated for their lease and establishment, knowing that their market value may change?

The questioner is only required to pay zakat on the value of the commercial goods. There is no zakat on the shops themselves or their decorations, unless they are prepared for sale, in which case they are valued annually and zakat is paid on their market value.