Wozer this is a big question to unpack! We've all come across this concept before. We've indulged in it, forgotten about it, avoided it on purpose, or replaced it with a sense of routine.
Routine and consistency are two different things. Mentally, there's a difference between a routine and creating consistency in regards to performance/skill.
Most of us thrive on some sort of routine, because this provides us with a sense of stability which helps us layer on other aspirations in life. ie; if you have a scheduled work life from week to week, you can plan ahead for social events etc. giving you more purpose and fulfillment overall.
But why is consistency such a hard task to accomplish? maybe it's because we aren't robots and we fluctuate with our level of determination. Or that the task we want to be better at, takes a lot of due-diligence and constant attention before seeing results. So we end up losing interest or get frustrated before even scratching the surface. Personally, I am guilty of the both.
I think this is because we put a different level of expectation on having a routine vs being consistent. Routine is schedule based, consistency is performance based. We tend to be harsher in our own analysis of our performance than doing something on time.
The secret here, is maybe to let go of our own pressure to perform, and just perform at our best, then and there.
When I look at this through a fitness lens, this is very applicable, and a more constructive approach. Only then does it seem doable to have consistency and a routine exist cohesively in someone's timeline.