There's no lounge car for coach passengers on the single-level long-distance trains, and that's been so for years. It's not like the scenic parts of America are entirely west of Chicago and New Orleans. (Did Amtrak have lounges on single-level-LDs before Viewliners? Did the pre-Amtrak railroads have lounges for coach passengers? Honest questions for both, not merely rhetorical.)
And on State-sponsored routes, business-class passengers who've paid a premium fare may not be in high-traffic if the biz-cafe is on the end of the train, but they get the (in my experience, moderate) noise and "lots of smelly food" (oddly enough, food usually has a good aroma to me). I've been in biz-class on the Lincoln Service, and it's not the third-world hell you're making out a half-cafe to be.
I definitely don't have comprehensive knowledge of the world's passenger trains, but a combo cafe-coach or cafe-business car doesn't strike me as either rare, radical, or anti-passenger.
Where are you getting "loss of tables" from? The drawings I've seen have an area of "cafe seats" in the cafe car, separate from the "coach seats" in the same car. If you're putting a lot of weight on the word "seats" to mean not-tables, the drawing of the diner car uses the phrase "diner seats" and I doubt Amtrak intends passengers to eat meals in their laps.
And why not have skylights or overhead windows in the coaches? As a substitute for a lounge car, no, I agree with you. But just as some people want to go to a lounge to socialize, others may want to have a better view of the scenery
without leaving their own seat and entering a more social space. Don't the Swiss run scenic trains with overhead windows in coaches and lounges? (Again, an honest question, not a rhetorical one, I'm not sure.)
You seem to be lumping in the apparent loss of the Sightseer Lounge with other unrelated (IMHO) issues. There could be overhead windows for views in cars with sociable lounge seating
and regular coach seating. A car with lounge above and cafe below wasn't handed down by the gods. There's no reason a replacement bilevel set couldn't have an upper-level lounge with coach seating, sleeper rooms, or even baggage on the first floor.
If the object is to complain to Amtrak in hopes of revising their
not set-in-stone plans, focusing on the actual problem with the plan (no lounge for coach passengers) seems more productive than insisting that Amtrak hates passengers unless we get the Sightseer Lounge with cafe on the ground level or if it dares to put food service and coach seats in the same car.