The Pelicans looked good tonight. If they can somehow clear some space to add a Paul George type wing, they become a top 5 team
They can't. So your premise is a moot issue. Most teams also would benefit by adding a Paul George type wing including us.
? Why can't they?
As there is a concept of a salary cap. It prohibits a team from spending money above a certain threshold. It penalizes teams without any frugality, financial knowledge, and sometimes owners conscience. https://www.basketball-reference.com/contracts/NOP.html
ATM the 2018/19 cap is projected at 102 mils $
They have already invested $94,827,090 for that year, that is without DMCs new deal that starts at 30,6 mil $ ($136/4y).
If they sign him, they are some 25 mils $ above the tax. That makes the PG13 signing virtually impossible, as he will seek the same money as DMC (7-9 year max).
answer to your question lies in the fact that:
1) NOLA has sent each of its 1st rounders picks away, every year since they drafted AD, relieving them of the possibility to have cheap long-term contracts. They weren't patient and it backfired. They peaked (this year) at 50% ball with a SStar on the roster.
2) Also, they signed some poor value contracts in consecutive years. Asik-Ajinca-Hill
3) The worst medical staff in the league. It indirectly lowers the value of their players and scares some potential free agents away. They didn't get anything for Anderson nor Gordon who walked away for nothing and are enjoying healthy and productive years after their leave.