Yes, I agree with this op.
It was hard to know what to think or say after your first post as there was no detail as to age, situation etc.
I do think that, given you are relatively young to have dc this age, and have an active, busy, working life, they certainly won't be worried you are sitting at home needing company.
They are at a busy phase of their life and, while you were clearly more settled at their ages, many people now in their 20's are still finding their feet really. I think a bit of distance from parents is important in that - and it is why nature makes our teens decide we are cringeworthy and boring! It's a natural process of breaking away. I do accept they are getting quite old for that, but not outside the more protracted timescale modern society tends to allow for it.
I am sorry that you miss them and would like them to see more of you, but you are definitely at a stage of life you should be busy and doing your own thing too. My dc are younger and , while they are my great joy, it must be quite nice to be a bit free at your age as well? Kick your heels up op, keep talking to them, and I'm sure they will recalibrate back towards the family base as they get older. I talk to my mum almost daily since I became a mum. as I relate to her so much more. Getting older and maturity go a long way towards appreciating your parents, and seeing them age increase our protective instincts towards them in a sense too. I think your dc are just taking their time with that maturity process.
Were you in your 70's and they had families etc, I'd be thinking it was more unusual.