Soil is important for plant and therefore all animal life. One of the most important aspects of soil insofar as vegetable growing in concerned, is that of soil texture. Of course the acidity or Ph level of soil is also important, but this little detail can normally be rectified relatively easily. Not so with soil texture.
The soil texture - that is to say, sandy, loam, clay and silt soils - has been built up and determined over many years - centuries even. The only exception to this being if your soil has been imported from another area - as is sometimes the case with new house building projects, or if your predecessor was an avid gardener for many years and in that time, altered the basic structure-texture of the soil.
If you have inherited a specific type of soil structure for your vegetable plot - such as sandy or clay soils, then it will require massive input of time and materials to substantially change that soil. That is not to say that any soil cannot be improved. both Clay and Sandy soils - together with all those soils types that fall between those extremes - can be improved considerably with the simple addition of organic matter.
However, if you have a clay or sandy soil for your vegetable plot, then it will remain that for the foreseeable future. Far better to find out how to manage that particular soil, and more importantly, grow the vegetables that are suited to your own soil type. Whilst we are basically addressing the subject of physical soil texture, the same is true of the other consideration for garden soils - Soil Ph level.
In any of its many and varied forms, soil is a complex mixture of basic elements. If one of these elements are missing, then it is no longer a 'soil'.
There is a more substantial article on garden soils here.