i can tell you, unambiguously, that it has always been this fast. those tilesets are almost certainly statically cached and served at lightning speed with practically 0 overhead from some regionally located cdn server.
server load would have a statistically imperceptible impact here; never seen a google product roll out with scale-related issues, especially one as mature as their gmaps architecture was at the time of the GL switch.
EDIT: the image-based maps is a great example of the "Choose Boring Technology" thread [1]. the benefits of the GL maps, IMO, do not justify the enormous speed sacrifice, at least to the end users. i'm sure google's ultimate plan was/is to merge google earth and "3d/vr/augment all the things!", but for basic maps it is just terrible. i'm really sad about the whole situation because they really have great looking, readable tilesets, much better than OSM (even if less complete). sadly, they never did get the pixel-density-appropriate versions made for mobile devices and all the features looked tiny when implemented using their js maps api :(
Sponsored listings and ads in map search are already a thing on mobile. If I search for certain common terms ("Smog Check", for example), some pinpoints are already highlighted differently because they correspond to ads in the search results list.
