Dear Esther started out as mod and is a very simplistic game... I doubt developing it was overly expensive. Amnesia was a strong IP so while it's true it sold well for a game of its size, it also faced a lot of well deserved criticism due to being notably inferior to its predecessor. Rapture statistics are less than relevant to this discussion since the development "issues" pointed out here happened before its release... so I stand by my statement.
And yes, from a business standpoint, I'd call Hello Games "mediocre" as well. Definitely not someone I'd be providing with too much resources.
I get the impression her husband was handling the business side of things, while her job was primarily as an artist.
We are discussing business here, therefore sales are important to the matter. Sony invested in Everybody's Gone to Rapture and it turned into a profit. You may want to dismiss this to try and prove your point, but it still is the exact same topic.
So let's go into details here:
Dear Esther (as a game on Steam, not a mod), cost $55,000. It got that investment back in 5.5 hours in 2012. It was also the best selling game on Steam for a time. Way above some AAA titles, in fact, during that period.
Amnesia: A Machine of Pigs was definitely not as acclaimed as the first game, but it is also a very different one and I get the feeling that you disregard it sorely because you don't like what the game focused. But since you are questioning Jessica's skills as a businesswoman, let's go back to sales. It got profitable in the first week. 120k. 400k in total (until October of 2013, so more now). SOMA sold 92k copies in 10 days. That's more time and fewer copies. And SOMA is being highly praised all over the press and with many fans. I don't have the numbers for Amnesia: Memories, but I don't think it sold as well. So this isn't because of a franchise or a studio behind it. It sold well because they did a proper job. Period.
Everybody's Gone to Rapture had a lot of hype since 2013. Not widespread, but surely enough to get the attention of a lot of people who like this kind of game. It was exclusive to PC, until Sony got it. Do you really think they would do that if they considered the studio mediocre? They knew its value. And it sold well in the end. So any kind of ill treatment that might have happened (and we can't know what happened) was not OK. And it proves that there is an issue on the developers/publishers relationship.
Finally, Jessica is the Director of the studio, while Dan is Creative Director.