Yamaha people seem to have information that longevity is 15 years for an electronic instrument played 15 hours a day. And then the instrument value has $0. The contention is this is a cost savings because there is no tuning or repairs compared to an acoustic piano.
Let's do the math. I could figure in inflation but let's use today's dollars.
You buy a Clavinova for $10,000, and a P22 for $10,000.
After 15 years, you buy another $10,000 Clavinova, with zero maintenance, if you're lucky.
After 15 years, the P22 would have cost a minimum of $5000 to tune and maintain, plus a new set of hammers for $1500, for a total of about $6500.
After 30 years, you buy another Clavinova, for $10,000
The P22 is still going, but it cost $6500 to maintain.
After 45 years, you buy another Clavinova, for $10,000.
The P22 is still going but costs another $65000 to maintain.
After 60 years you will have spent $40,000 for Clavinovas with no maintenance costs, but it's worth $0.
After 60 years, you will have spent $26,000 for maintenance, plus the initial investment of $10,000, for a total of $36,000, but you will have a piano worth $3000. Net cost of the P22, $33,000.
I realize there are a multitude of other factors to consider, on both sides, but in the long run, electronic instruments are not less expense.