Landing probes on Venus has been a low priority because it really offers poor value to send something all that way only for it to die within a few hours of landing in the acidic pressure-cooking hell that is Venus' atmosphere. Venera 13 and 14 lasted 127 and 57 minutes respectively. That sounds awful, but the design goal was just 32 minutes! Perhaps our inability to have any kind of presence on Venus' surface has reduced interest in orbital missions too, which is a shame.
Until we can get close to self sustaining infrastructure sending people into space seems really pointless. If we could even get something like Biosphere 2 to actually work that seems like a solid first step.
BIOS-3 seemed to work, but Dried meat was imported into the facility, and urine and feces were generally dried and stored, rather than being recycled.
Because with limited resources for space exploration, it makes sense to actually explore someplace where humans could actually land in the near future and maybe has life. Any serious exploration of Venus would be pretty demanding.
Mercury, Gemini and Apollo were standins for open war with the Soviet Union, so they got more war-like funding and focus. 'Terrorists' aren't going to be shown up by space travel and no one believes we're really at war with the Chinese so no one is willing to throw money at it.
The US has never really funded anything that isn't related directly or indirectly to war, that includes Space Exploration.