Indeed, rollover jackpots can raise the expected value of a ticket (in dollars) above the price of the ticket - as long as nobody else wins and makes you split the prize with them.

Wouldn't the expected value include such occurances?

There are also slot machines in Vegas that operate on a similar rollover principle - the more money that is put into the bank of machines, the larger the jackpot gets, and that can eventually give the machine a positive expected value for the player.

Peter Liston, a prominent figure from MENSA in Melbourne back when I used to be a member there, used this as his primary form of revenue. (Australian slot machines not Vegas ones obviously). He objected somewhat to the term 'Professional Gambler', observing that once you do it professionally the term becomes very nearly oxymoronic. It's the only investment he makes that consistently makes money. Stockmarket investment is far less reliable than a known RNG over a significant number of rolls.