Of course they are, not many people who own two houses on different sides of the country are worth less than $1M.
"Casa de Portnoy East" is appraised at $505,800.
How do you know how much his house is worth?
Not going to give more details because I already feel uncomfortable about posting something as personal as the appraisal. But obviously MP has posted a lot of pics and info about his house, and real estate transactions are on the public record and easily available on the web.... so it's not very hard to connect the dots.
Anyway, that price was a market appraisal for property tax purposes... he's the original owner, so it could potentially sell for more or perhaps less. And as Bosk pointed out, we don't know if there's a loan or not.
But forget the houses, you can also look at the income, they've sold over 10 million albums globally, so even if they only takes $1 in royalties after expenses, that's still $100k/year each averaged over their career... and touring is more lucrative than album sales. Factor in side projects, etc. and they should be making $200-500k per year before taxes. As long as they've been prudent with their saving and investments, I'd be shocked if they aren't all worth in the low millions by now.
That said, I totally agree with what has been pointed out a few times... their income isn't guaranteed to be sustainable, they have families to support, they probably plan to live 40 more years, and right now they have higher earning potential than ever. Taking a hiatus would have been VERY costly, people in their 40s/50s generally don't gamble with their retirement savings like that.