1) You are totally correct in your assertion that due to the nature and density of habitation of the US East compared to the US West, this makes finding paleoindian sites much more likely. This does not, however, explain the reliable difference in lithic technologies associated with specific, time-indicating geologic strata in different geographic regions. When it comes to this particular question, a stone point is not a stone point is not a stone point.
2) Your assertion that Souletrean hypothesis is predicated on a comparison of stone tools associated with "Clovis, New Mexico" is completely incorrect and suggests you don't know much- if anything- about this topic but nevertheless tried to Google-Fake-Knowledge your way through it. The Solutrean Hypothesis supporting tools in question are yielded a) mostly from the Delmarva area and B) from context indicators suggesting timeframes WAY before the Clovis range. While that particular area of lithic technology is named for Clovis, NM (since that's when they were first discovered in the 1920's), Clovis tools have been found everywhere in North America but chiefly associated with the westerly locations and in a timeframe roughly 13,000 BP. That leaves an intervening 5,000-8,000 years for the two to commingle or influence each other (thus explaining why Clovis bears such a striking resemblance to Solutrean technologies)
Whether or not Solutrean Hypothesis is ultimately correct is something historians will have to decide on, but I'm just old enough to remember all the strident and "CASE, CLOSED!" theories that were presented about the extinction of the Neanderthals... how smug and confident various 'academic establishments' were until OOPS! Turns out this weird, new technology called "DNA Sequencing" revealed the presence of Neanderthal DNA in specific groups of human beings, thus shattering everything the 'experts' once claimed. There is pretty compelling stuff for Pre Clovis / "Archaic" peoples in North America who may have not come from Asia and who may or may not have made much- if any- contribution to the larger genetic makeup of present day NA's.
Sorry to necro an old post but for whatever reason, this ranks in Google and there were a few errors that needed to be corrected.