If you look at a product and there is a major design decision that is contrary to your needs, then the product is not suited to your needs. Of course, you can suggest a feature because the customer is important to the success of a company. On the other hand, the customer is a group of people as far as a business is concerned. They have probably done their market research to see what the group that they're trying to serve needs, and made design decisions based upon that. If they cannot meet the needs of a particular customer (or a group of customers that is outside their target demographic) in an economic manner or in a manner that will satisfy the group that they are trying to serve, then it is contrary to their interests to do so. In fact, they may be obligated not to do so if it hurts their profitability.

As a consumer, you have options to deal with this. You can choose a company that better reflects your needs. That is one of the benefits of a competitive marketplace. If no business meets your needs, you are free to create something that does meet your needs. Since there are a number of ereaders that are open to modification, including Kobo products, and a vast body of open source software to base your ideal reader on (ranging from support libraries to full ereading applications) the problem is within the scope of an individual. Though, admittedly, it would be a skilled and determined individual.