I agree that the rise of MySQL is combined with using RDBMS as a table store rather than a relational database, but I am not positive that this was driven by RoR and ORMs. Every large-scale system I have worked with that utilizes MySQL (and I'm on at least my third in a row of these systems, sadly!) is/was driven by application-logic database utilization via the "FriendFeed model" - that is, a big fat ID->Document Blob table for persistence and breakout tables for indexing.
ORMs and ActiveRecord in particular encourage, to some extent, the use of a RDBMS, even if they didn't get to take advantage of them well for a long time - for example, in RoR "has_one / has_many" for foreign-key relationship, .joins(:field_name) for, well, joins, and so on.
Perhaps. Something happened between those first-generation web sites where you were writing SQL by hand -- so you could just as easily be writing (injection-attack-prone) queries that made use of stored procedures etc -- and today.
A big reason I called out RoR is that back in '04-05 I was railing against its default use of plural table names, and DHH on IRC recommended I shut up and just flip the configuration switch and turn off the feature, but of course when I did that all sorts of latent bugs were exposed.
RoR was the beginning of hipster "coding" and I therefore blame it for everything.
I'm wasn't previously familiar with the FriendFeed approach to database (ab)use. I paid about as much attention to it as I did to MySpace back in the day -- nearly zilch -- so its etc innards are doubly obscure to me.
ORMs and ActiveRecord in particular encourage, to some extent, the use of a RDBMS, even if they didn't get to take advantage of them well for a long time - for example, in RoR "has_one / has_many" for foreign-key relationship, .joins(:field_name) for, well, joins, and so on.