Small Business Prosperity Act of 2019 This bill amends the Internal Revenue Code, with respect to the deduction for qualified business income, to (1) make such deduction permanent, (2) limit to 21% the top tax rate on qualified business income, (3) repeal the limitation on the deduction based on amount of wages paid, and (4) revise the definition of "qualified trade or business" to mean any trade or business other than the trade of business of performing services as an employee. The bill provides that a change in the organizational structure of a corporation is not a taxable event if there is no change among the owners, their ownership interests, or the assets of the organization, The bill repeals the estate tax after 2019.