Why are some businesses legally organized as partnerships rather than as corporations?

Why are some businesses legally organized as partnerships rather than as corporations?
The choice of the form in which business owners want to do business (i.e., as a partnership or a corporation) depends on what the owners consider to be most advantageous for them.
The advantages of having a partnership is that all owners have an equal say in all partnership decisions, and they share profits equally (unless they have a partnership agreement that states otherwise). If a business's owners want to be the ones actively managing the business, they'll want to manage the business as a partnership. In a corporation, the owners are the shareholders, and shareholders can generally sell their ownership interest freely. But even though they are the owners of a corporation, unless the corporation is very small (and special rules apply to small corporations) the shareholders do not manage the corporation or make business decisions for it. Instead, the shareholders elect a board of directors, and the directors choose the executives who will manage the corporation's business. But it is possible for a small corporation composed of a few people to become an LLC instead of a partnership. However, they must comply with the relevant law to do that, and that includes filing with the state.
A second advantage of operating as a parnership is that, if people do business as a partnership, they don't have to file separate income tax returns for the partnership. Instead, each partner simply reports his share of partnership income on his or her own personal income tax return.
A third advantage of operating as a partnership is that no filing with the state is required. To set up a corporation, legal documents have to be prepared and filed with the state of incorporation, and there are fees involved. Furthermore, a corporation must pay income taxes and file its own income tax return annually.
But there are disadvantages to operating as a general partnership. If people are doing business as a partnership, they can each be held personally liable for harm caused by any of the partners if the partnership is sued. So if partner A commits a tort in the course of business and is sued by an outsider, the outsider can sue not only partner A, but all of the other partners separately, as well as the partnership. And if the outsider wins damages that are more than the partnership assets are worth, the partners have to make up the difference out of their own money. And what is worse, the partners are jointly and severally liable. So if your partner commits a tort and a third party sues you and your partner as well as the parnership, the plaintiff can choose to collect the entire amount of the judgment from you, and you would have to try to get the other partner to contribute his share.
Clearly, doing business as a general partnership requires a great deal of mutual trust among the members.
The chief advantages to doing business as a corporation are:
1) Perpetual existence: When a partner leaves or dies, a partnership is technically dissolved by that event. Partnership agreements can provide otherwise, though. But a corporation can, in theory, exist forever, because in the eyes of the state, a corporation is a separate entity, apart from its owners.
2) Free transferability of ownership interest: Shareholders of a corporation can usually sell their shares at will.
3)Limited liability: this is the major advantage of doing business as a corporation. If a third party wins a judgment for damages against a corporation, he can collect only out of the assets of the corporation, and not out of the personal assets of the owners. But a corporation must adhere to the laws governing corporations to get limited liability treatment; if the corporation was merely set up as a "dummy corporation" without sufficient funds or assets, a court may treat it like a partnership, so the the personal assets of individuals could be attached to satisfy the judgment.