When you say resources I will assume you are mostly focused on fuel costs, which is where you would presumably save money by taking advantage of a horizontal airplane-like takeoff. It turns out airplanes and rockets have very different economic operating costs. Lets put some numbers on it. For simplicity we will consider the SpaceX Falcon 9 and the Boeing 777 (in particular a 777-200 which is used for routes like NYC-London).
A 777-200 costs about \$300 million and has a lifetime of around 40,000 cycles. As a rough estimate this means the amortized cost of a flight from NY to London would be on the order of \$7,500. The fuel costs for the same flight will be around \$30,000. From quick googling it seems like the hourly total cost would be roughly \$30,000 / hour of flight, so the whole flight cost would be north of \$100,000. Regardless, it is easy to see that the cost of the aircraft itself is a small part of the total cost of a flight.
A Falcon 9, on the other hand, costs perhaps about \$60 million to build (exact numbers aren't available but most estimates put it in that range). Right now the reusability record sits at 5 times, but lets be a bit generous and say it's possible to be reused 10 times without refurbishment. That gives us a per-flight cost of \$6,000,000. According to SpaceX the fuel cost of a flight runs at \$200,000. We can quickly see that the vehicle cost is a very significant cost of a single flight. SpaceX puts the cost at 0.4% so our estimate of 0.033 appears to be in the ballpark. Even if we were extremely generous and figure it can fly 100 times, that still means the vehicle cost per flight is significantly more than the fuel cost per flight, a complete flip from how airlines operate.
So what would you gain with horizontal airplane-style takeoff? You might be able to reduce that fuel bill by a bit, lets again be generous and say you'd save \$100,000 per flight. What would you lose? As the other answers and comments illustrate: quite a bit. You would have a massive increase in the engineering challenges you need to address (which means more development costs), but more importantly, you are introducing so many more places for things to go wrong. Not only does it still need to perform like a rocket does for the upper atmosphere, you have to have it work like a airplane in the lower atmosphere. It would also need to flawlessly transfer between these flight profiles.
TLDR: It doesn't work because at best you save a little bit in fuel costs but add massive engineering complexity and reliability issues.
Note: the numbers used are rough estimates from quick searching, but I believe they illustrate the economics of the issue. Some sources include:
What is the cost breakdown for a Falcon 9 launch?