The issue in such apps/businesses is "greed". Everyone wants to save as much as possible. Based on this entrepreneurs go to Upwork, People per hour, and other services to order the cheapest solution for their business. They don't know about UX or OOP and think that freelancer and companies are the same.
When a software company says "we need 2-3 weeks to work on UX and Technical Specification" this sounds like a nonsense for them. = "why I should pay for something that is clear enough".
As for the difference between a mobile app or responsive website, I agree with Mickey Hovel
. It depends. It depends on business aims.
There are a lot of specialists, that can analyze business aims, market, technical part, competitors and provide you with a solution for your business. The question is "Are you ready to pay for this?", if you don't, then don't say"Oh, this f*** developers". If you have a good developer even Responsive mobile design could be great and achieve all your aims.
Personally, I believe that there is nothing better than mobile app solution:
1) It is a great PR-step. Every user will think "wow. they have the mobile app - these guys are detailed orientated and think about such users as me"
2) It will open new markets: "Google Market", "App Store"
3) You can analyze and track your targeted audience and update your business based on users preferences. (but the same could be done and with website)
The main thing that everyone should take into account is: "Responsive website, mobile apps - all these are just tools for your business". If you take care of your business like of your child - don't buy "synthetic clothing" or not healthy food.