Ohh I get the problem.
You have to think about what you're doing beforehand. Sounds like a real problem.
Going 150 LY doesn't take a full hour, even in a Corvette. Ignoring that hilarious fact that the Vulture, the source of this thread, can have pretty good jump range, you're trying to use random numbers to prove a point? Where does 4 million vs 3 million come from? Do faster ships have a travel time of exactly 0? Combat ships have a travel time of exactly 1 hour?
Your whole example falls apart with any...anything.
The numbers I gave were just a hypothetical example for what a player might come across with regards to speed vs combat effectiveness, just a series of ballpark estimates as a point of reference. Corvettes kill things faster and more effectively than faster ships, such as an Asp or a Diamondback or even an Anaconda; it might give 4v3 million, it might be 5v2 million, it all comes down to your loadouts, mods, preferred targets as well as simply what the environment decides to throw at you. However, a Corvette with a maximum jump range of less than 15ly (unmodded A-grade corvettes with full combat load are about 11.5ly), particularly if it doesn't have a fuel scoop or additional fuel tanks to save space for additional combat equipment, will certainly take far longer to get anywhere than a longer-range ship. It might not be 1 more hour to get somewhere compared to a faster ship, but it will take longer, and that's the principle here.
Which brings in the question: Are you willing to spend the extra time on travelling? Is it worth it? Some people aren't willing to put the time and effort in to get the slower ships around and would rather use the faster ships, sacrificing potential upon arrival for the ability to spend more time at the destination. Others, however, are willing to put the time and effort in to bring their unstoppable yet glacial vessels to bear, sacrificing a bit of time at the destination in exchange for greater combat potential.
Traders see the exact same tradeoff (pun not intended). Many traders have to make the choice between ships with good cargo capacities vs those with good jump ranges, is it better to haul 40ish tonnes of goods in a DBX with a journey of 3 jumps on a decent traderoute or to haul a 100ish tonnes in 5 jumps with a T6? Depending on what you prefer as well as the availability of rare goods and data delivery missions, the answer of which one is "best" can vary.
And I don't quite get your italicised usage of "think", it seems to me almost like you consider giving players meaningful and impactful decisions that they have to think their way through rather than just automatically getting the best of everything at once is a problem.