A pyramid scheme is a business model that recruits members via a promise of payments or services for enrolling others into the scheme, rather than supplying investments or sale of products or services. As recruiting multiplies, recruiting becomes quickly impossible, and most members are unable to profit; as such, pyramid schemes are unsustainable and often illegal.
Pyramid schemes have existed for at least a century in different guises. Some multi-level marketing plans have been classified as pyramid schemes.[1]
https://en.m.wikipedia.org/wiki/Pyramid_scheme
When you boil it down, all the Church wants from its members is for them to go out and get more members. Either by serving a mission, recruiting friends and neighbours or work associates, producing children or even recruiting the deceased. Everything about the Church comes down to recruitment.
Members pay a monthly subscription (tithing) for the privilege of being able to sell the product (Mormonism) with a promise of great rewards. When you buy the product, all it is is a requirement to go out and sell more product. And the only people benefitting financially are those at the top of the pyramid.
An argument can be made that the LDS Church is a pyramid scheme.