What are the positive and negative impacts of marketing intermediaries in sales?

Marketing intermediaries are key factors / players in some sectors like toursim and hotels.

We need marketing intermediaries to sell our products and they are vital in our sales process.

It impacts on selling prices resulting in higher selling prices and consumers at the end is penalized

Marketing positive impacts would be obviously many leads and awareness of service and products and negatives as my friend mentioned as companies spend more than20% on marketing and advertising of products it makes price go up which effects customers directly or indirectly

marketing intermediaries like resellers - agents - web sites etc will affect selling prices with their % commission they will obtain but as the same time they create more sales potentials and product branding.