No response is almost never a decision; it's a queue. Your email landed third in a triage pile behind two fires, got mentally filed as “reply when I have an answer,” and aged out of the inbox's working memory. Every day after that, replying gets more awkward and therefore less likely.

Which is why volume doesn't fix it. Five copies of the same ask deepen the awkwardness; what reopens a thread is changing the ask, the value, or the channel. Persistence wins follow-up, but only persistence that brings something, which is why “just checking in” has never reopened one.

Take the trade seriously: offer a slot far enough out that “slammed” stops being a reason, and put it on the thread so a yes takes one word. If even that gets silence, the ask is still too expensive.

Shrink the ask as the silence grows. The first follow-up can propose a meeting; later ones should ask a question answerable from a phone in an elevator. Replies track effort required, and silence means the current ask costs too much.

Then switch channels deliberately. Unanswered emails are an argument for one phone call, and the call you're avoiding is exactly the one to make: warm, unbothered, with a reason for calling that isn't “you didn't reply.”

“Still on our list, I promise.” A promise without a date is a deferral with better manners. Offer the slot anyway; the booking or the dodge is the real reply.

“Can you follow up next week?” Take it literally: book the slot now, on the thread. Vague deferrals are where follow-ups go to retire.

“Looping in my colleague.” Progress disguised as delay. Treat the new name as the real buyer and restart discovery one level deeper.