Essentially I agree. But there is nothing wrong with planning things in stages. One can plan a big multi-level empire, with having a single deck, or portion thereof, that has a self contained layout… loop or point to point or single large switching industry.I think trying to do a complex 'layout', multiple loops, multiple levels, tons of switches all on a 4' x 8' is a killer. You just can start with something like this and hope to bring it to completion with is all running well and scenery completed. Not saying yours is, but beginners dream too big. I found starting with a simple point to point or something like the "Gum Stump and Snowshoe" is plenty to do for a beginner and gives them operation time too. Expand or redo gradually, this gives you time to figure out what you like, what you are capable of doing, and tempers the future with experience.
Since tracks on the floor I am on my 9th railroad. This will be my smallest one in physical size, 14" x 72", HO scale. With luck it will be expanded over time and eventually go around the room as a shelf railroad, point to point, about 80' in length. But my plan is not to expand until I complete my list of 'must haves' on the 14" x 72" section.
It is rewarding to having something operable, to run trains, while 80% of the big picture still needs track laid. On the other side of the coin, that unfinished 80% could fall to the back burner and never get done if you allow yourself to lose focus.
Unlike CTValley, I do “daydream” about my big picture quite a bit; mostly in mental ops. I do this to, hopefully, discover potential goof ups or improvements before benchwork is even built. I also do a lot of measuring. For instance, I recently decided to down size all my mainline trains from 3 locomotives to 2. That allows 1-2 more car lengths per train while staying about 11ft long. I also long ago figured a reversing wye wasn’t needed… but I’ve changed my mind. Adding it won’t take much, eliminates the 0-5-0 switcher by 100%, and will provide a better industry spur lead as well.
I also don’t lose focus because “daydreaming” keeps the big picture in the front of mind, not the back.