After reading this, I acted on a decision I was on the fence about. I already have moved to Bitwarden and like it a lot better, but this post prompted me to go into LastPass and actively delete my account. The next thing to do will be to start changing passwords. As with most of us, that's a project of serious scope that I do not look forward to.
When I first moved off I didn't want to close the account just in case something went wrong with the transition. But after it was clear that the transition was fine, then I should have gone back and just finished up the final step.
I probably needed to do a full account cleanup anyway at some point, but I just wish I had been slightly more proactive about deleting my data. It's a good lesson to learn, I'm thinking that as part of the account cleanup I should also take a look at what other accounts I have lying around that are unnecessary.