yes you can, although you might think of it as stop gap rather than 'good for another 15 years'. we knew we were going to do a total redo in 5 years or so when we bought our house, so i put inexpensive subway tile over a small mosaic that i didnt like at all. not a single tile let go in the 6 years til we redid.

the other thing to consider is do you have the depth for another layer? the sticking point may be behind your sink faucet, as a lot of times space is close there.

its still a big professional job; outlets need to be moved out for example. you'll save on demo costs and dust, but thats it.