making, for example, the new LP plugins available to non-sonar users would give cakewalk an extra line of income

+1, when I have used other programs such a thing has been visible right in the "start page." Studio One, XLN, etc., have links right in the main program to bonus content to allow users to try them out right away, and then purchase them if desired. Such a thing could target both Cakewalk and non-Cakewalk users (but for them, the "how to try" would be trickier).

i expect this is where the start page is headed, at least it should be; cakewalk might take note of the quite unobtrusive nature of the studio one newsfeed/ads

as well as pitching to current users via the start page, cakewalk should offer inhouse plugins (like recent LP) as VSTs separately through the shop, thereby gaining additional non-sonar customers; in the past this has been dismissed due to unacceptable extra support strain but recently VST instruments have been available outside sonar, so maybe that's old reasoning by now?

YES! I've always wondered why they don't do this. If the new LP EQ/MB or some of the old plugins like Sonitus Delay are really that great and better than any of the competitor products, then non-SONAR users will most likely buy them if they are sold separately at a reasonable price (Sonitus effects used to be sold separately, but probably didn't sell well because they were 32-bit). I don't think anyone's going to buy SONAR just because they want to get one or two of the bundled plugins, especially if the plugins don't work in other hosts.