Why do you think this strategy became less viable in the 1990s?

Here is my answer

By the 1990s, the international strategy that Procter & Gamble pursued became less viable because the companys growth of profit was declining. The problem vested in the fact that administrative, manufacturing, and marketing facilities were extensively duplicated by Procter & Gamble, thereby driving up its costs. In addition, barriers to cross-border trade were decreasing at a rapid pace worldwide and fragmented national markets were merging into larger regional or global markets. Also, the global retailers through which Procter & Gamble distributed its products in the past were growing larger and more global and were demanding price discounts from Procter & Gamble.

Those 4 reasons that I highlighted. I know that they played a significant role in causing the international strategy of Procter & Gamble to become less viable, causing the company's growth of profit to decline. I would like to know how each of those 4 reasons played that role. Explain it to me so I can understand it more clearly. If you can provide detailed explanations for each one, I would appreciate it because it is very important for me. Thanks.