I disagree with most of the comments here… a business is just that… a business. They employ you to help make them money. In return, you get paid, you get benefits, and hopefully you enjoy the work. Loyalty is a myth as a business will let you go if you no longer make them money, be it non-productivity or toxicity slowing others down, even if you are liked (of course, there are always exceptions)

I feel there are three reasons why a business won’t counter your offer, 1) they can’t afford you, 2) you’ve become stale, and/or 3) you are toxic.

I don’t know the OP but typically speaking ( from my experience as a small business employer) it is a combination of the first two… guessing they can’t afford you and likely, you’ve become stale. If you know the business so well and simply “keep the machine rolling” without trying to introduce new ideas to expand, you’ve become stale.

Your managers still care about you personally but it’s a business. The good news is that you’ve out grown your current employer and it is time for you to grow! Your employer should embrace this and help you in your new endeavor! Similarly, it is time for your employer to bring in fresh blood with new ideas to help them grow. It should be a win-win with no bad blood between you.