Last time I was at Google for a workshop (If you have the chance to visit Google, do it. The food alone is worth it), they didn’t seem to push CloudSQL a lot, because they wanted to guide people more in the spanner direction.
Without a solid RDS counterpart however, I don’t think bigger companies will consider moving from AWS. Happy to see they changed their mind and continue to expand their SQL services. The competition by Google put a lot of pressure on AWS who seemed to be gotten a bit lazy. Google was ahead of the game with their global load balancers and network speed and quality. Now AWS countered with their 5th series C5/M5, which solve the bandwidth problem of the smaller C and M instances