I'm not implying that this was made on purpose -- vendor lock-in might happen "naturally" as well, when company becomes big enough that they can start unilaterally change prices/conditions/services knowing that costumers will accept that (even grudgingly), because they have nowhere else to go or it is too expensive/complex. Google is the perfect example of this strategy. Smaller player or startup would probably go bankrupt very fast if acted with such disregard for their costumers.
So far I've seen only one customer notably affected, and (judging by the post) I doubt they'll be sticking around on Firebase. There are a lot of take-aways for this story, but I don't think "vendor lock-in" really fits.