You're quite welcome. I'm sure that lots of titles had property which not part of the title - remember Rosings Park - but was generally expected to go along with that title. However, if the father was sufficiently angry at his 'heir to the title', that property might be given to someone else, although I expect that would be rather unusual (since the upper crust were apparently very concerned about preserving the standing of the family name, which is why they were so big on primogeniture). But for at least some titles, the title came with land which the title-holder was (sort of) taking care of for the Crown, and that land, and apparently any improvements, went with the title.
One of the things I've always been puzzled about was how common it was for rich people in England to spend all their money. In P&P everyone seems to assume they know how much Darcy has, but all they really talk about is the income from Pemberley. It's made clear in the book the family has had Pemberley for a long time, so it would seem likely they invested some of that income over the centuries, and it would further seem likely the income from Pemberley isn't all that Darcy has. From my reading, in those days someone with cash could expect to get a safe return of 4-5% on the cash (e.g.,the Funds), so likely there were investments with more risk which paid a higher return (sort of like the NYSE vs municipal bonds today).
The point of my tangent is that, if an earl spent every penny, then likely he wouldn't be able to do more than tell his heir to toe the line or get no allowance, which could then lead said heir to marry the daughter of a rich tradesman, which probably wouldn't be what the earl wanted. But if half his income is from investments which are not part of the title, then he has a bigger stick. So did most earls have that stick, or not? I have no idea.
