But as a team, the answer "I can't reach the expert because they secluded themselves" is not acceptable. Because as a senior figure on a team, you job is to become a force multiplier for others, not a solo force. Not to do work that magnanimously benefits others, but work that makes others better.
You need occasional deep work time, sure. But the whole "I must disconnect from everything, always" thing does not work for any social endeavor - and most meaningful things are of a scope that requires a team.
I wish I had a better answer here, because I too like thinking quietly for long times - but I also see that I fulfill a useful function when I'm reachable, and ultimately, you get paid for usefulness to the larger endeavor.
(This points strongly towards solo/entrepreneur tracks if isolation is your only useful mode of work, but even then, you'd be well advised to find a partner who handles the people parts)