American professional leagues assign incoming players through a draft rather than an open market, and the order of selection is the mechanism that keeps the system from concentrating talent. Every complication in that order traces to one problem.
Reverse order is the base rule
The default is that the team with the worst record picks first and the champion picks last, which sends the strongest available players to the weakest teams.
The purpose is competitive balance, since a league in which the same teams win indefinitely loses audience in most of its markets.
Ties are broken by defined tiebreakers, commonly involving strength of schedule or a coin toss, so no discretion is involved.
Reverse order creates a perverse incentive
If losing improves the next selection, a team eliminated from contention has a reason to stop trying to win, which is corrosive to the product.
This is why leagues where the top pick is decisive have added randomization, while leagues where a single player matters less have generally not.
A lottery breaks the direct link between finishing last and picking first, so the worst record buys better odds rather than a guaranteed outcome.
Lottery design has been tuned repeatedly
Early designs gave every non-qualifying team equal odds, which discouraged tanking but sometimes gave the top pick to a nearly competitive team.
Weighted systems restored the connection to record while capping how far a team can fall, and flattening the odds among the worst teams reduces the benefit of finishing last rather than third from last.
Each revision trades competitive balance against tanking deterrence, and no design eliminates both problems at once.
Trades make order a currency
Picks can be traded, sometimes years in advance, so the team holding a selection is often not the team whose record produced it.
This lets a rebuilding club accumulate future selections and a contending one convert them into experienced players immediately.
Leagues place limits on how many consecutive future first-round picks a team may trade away, to prevent a front office from mortgaging a franchise entirely.
Compensatory picks sit outside the order
Additional selections are awarded to teams that lose players to free agency, calculated by formula rather than by negotiation.
These are inserted at the end of rounds and are often restricted from being traded, depending on the league's rules.
The effect is to soften the disadvantage smaller-market teams face when players they developed leave, which is the same balance objective the draft order serves in the first place.