Guy in the grove is basically saying the same thing as the goblin.
"You're not the only one in need" = "I have other customers"
To which he probably does. Given that the Tieflings are getting kicked out and will have to trek to Baldur's Gate via the Shadowlands, many of them likely will want to stop off to pick up some supplies from him. To say nothing about the rest of the Druids who might want to pick up odds and ends from him (Given he seemingly has access to outside of the grove)
Goblin guy probably does have other customers.
Not necessarily right at that exact moment, but the other gobbos probably do buy things from him. Even more so with the chicken chase game on the other side of the courtyard from him, so if some drunk gobbo wins a handful of gold he might come over and buy something (Unless some random adventurer party is stood around taking up is time and attention for unreasonably long)
In fact, this continued patronage from locals would be an explaination into how these vendors restock their supplies and gold every long rest. While you're sitting in camp waiting for it to become night, other people are visiting them and conducting trades.
Rolan is just Rolan. He's also not overly fond of you.
