Let go of the guilt.
I always wanted a bunch of kids. It wasn't in the cards for me.
I got two 10 years apart.
I don't regret it.
The thing is that kids are all invividuals and you just have to find a way to spend one on one time with each of them. Of course, babies require more time, But, you can enlist the older ones to help you. And, you can make sure that you find a way to spend "older" time with your older kids so they don't feel left out.
It's a juggling act, to be sure, but I doubt seriously that your children feel they are being as cheated as YOU feel they are.
Different ages require different things so you can focus on each separately, include them in things they can all enjoy together. It's a juggling act, but you can enlist the older ones in things that the babies can't do and enlist their help with the little ones.
It's a matter of managing, that's all. You really don't have to feel guilty.
Best wishes.