If we take this idea that building a foundation is as simple as practicing and attending to the basics, then, in theory, there should not be much of a problem in becoming proficient at whatever you apply this to, or anything that you create. However, it goes deeper than that. There is one other issue that must be attended to before revisiting basics. This issue in question is the idea of motivation and practice. I could separate these out, but in the interest of brevity I will address them together. Motivation and practice are major obstacles in trying to achieve fluency and proficiency in anything. That is why I bring this up. If a person does not apply himself/herself, then there can be nothing achieved. Each person must find their motivation to rise up and drive towards that goal of excellence. Excellence goes further back than the fundamental basics, it goes to your motivation and drive to practice that which you know. The other half of that is how you choose to practice. Fortunately, in today's world, there is a plethora of information out there that can help guide you. It is best to have a good teacher to help you, but there are those who train more alone than with others, who are forced to find that information and knowledge to help guide them on their own. But there are many good teachers and sources of information to help guide your practice, you just simply need to take your time, do your research, and be smart about the choices that you make. Your time and energy are precious, do not waste them on bad practices. Any good martial arts teacher will try to guide you more than tell you their way is the only way. There is no one answer or way to practice or to learn. That part of the journey is up to each individual. Remember that. The way you choose to think, learn, and make choices is up to each person, and nobody else.
Your base knowledge, your motivation, and your practice are all fundamental parts of your foundation and that is where you skill, proficiency, and style of martial arts will grow from. Do not take them lightly and do not take them for granted. Remember where it all comes from and you will be well served in how you learn and progress.