Can monopolistic dead weight loss persist without government intervention? If so how? Can monopolistic dead weight loss persist without government intervention? If so how? I am researching monopolies and find dead weight loss proposed as an evil of monopolies but i can not find any examples or understand the reasoning behind it. I have seen the graphs and understand them but why would new businesses not enter the market if there are profits to be earned.
If I understand you correctly, monopolistic deadweight loss persists without gov intervention because of the following:

Economies of Scale: if monoplist is able to produce at below the market prices due to the presence of economies of scale, then the monoplist is effectively able to retain its dominance in the market as new firms entering the market cannot undercut the monopolist. Thus, deadweight loss persists.

Patenting: Monoplist could patent its products and process innovation. A new entrant would have to come up with a new idea of a similar product to enter the market tha the incumbet dominates. This however is not usually possible due to very high initial R&amp;D investment requirement. 

Rent-seeking: It is also possible that a monoplist could lobby governments in order to influence policy related decisions. Tobacco and weapons manufacturng companies are known to spend large sums on lobbying efforts. 

These effectively serve as barriers to entry.

In the presence of barriers to entry, monopoly profits effectively transfer income from households to the monopoly. The monopolist could also under-produce in order to maintain monopoly profits. Examples could be the production of "limited edition" goods which are usually priced above average market prices. Because the monopolist earns above normal profits, it may not invest in cost-saving technologies. 

In order to minimise or elliminate the deadweight loss, governments tend to invoke antri-trust laws and regulate the markets and industries. Deadweight loss persists in the absence of action by governments.