The 2005 return/reboot had a small budget and that could be seen in the props which mostly were ordinary items repurposed as out of this world technology. But that worked on the overall charm of this period - I dare to say that show felt realistic in that cheapness.
The regained interest surely allowed to assign more money to the series. DW was at the peak during 11th and 12th Doctors tenure with BBC America involvement in production - the low-quality is mostly gone and more CGI was utilized, and so the stories were good. Not mention the good chemistry between all main actors.
This is a pretty common scifi thing. The Borg antennas being built on the Enterprise's deflector in First Contact were bird feeders. Odo was once contained on DS9 in a bread maker.
Cypher -from the Matrix franchise- said it best, "Ignorance is bliss". Fun fact about that scene: Studio executives wanted it cut but Keanu Reeves insisted on using it.
There's a lot of people who have remarked on necessity being the mother of invention - I claim that it's possible to maintain that even when you're no longer constrained, but it takes a discipline often lacking in people.
If you know you have 2 weeks and 100k to shoot an episode, and that everyone from the top down knows more money and time isn't coming, then you have no choice but to deliver it, no matter the corners cut. It's very hard to keep that attitude and pressure if people are aware that the budget limits are a polite fiction if you're convincing enough. (One might draw parallels to Steve Jobs' remarks about how the most important thing is not knowing when to say yes, but knowing when to say no.)
One might look at Team Cherry (Hollow Knight, Silksong) for an example of maintaining this - they made an enormous amount of money off Hollow Knight's success, and instead of scaling out the team markedly for Silksong, they mostly used the money as padding against any pressure to deliver it sooner, and worked at their own pace, to their own satisfaction.
The regained interest surely allowed to assign more money to the series. DW was at the peak during 11th and 12th Doctors tenure with BBC America involvement in production - the low-quality is mostly gone and more CGI was utilized, and so the stories were good. Not mention the good chemistry between all main actors.