Sad but true. I have a friend on a market stall and he keeps getting offers to buy stamp collections but he can't shift them and the people selling all want a fortune for the albums.
It is not all bad though.
While the market was flooded with a ton of product in the 80s, stamps that are older than this do still have a market. Once you take away all the mass produced recent product and you start looking at the older, harder to find, items then you can see some that have held their value.
Granted, few new people are joining the hobby but there are a ton of old time collectors who are still enjoying it. They are prepared to pay good money for a stamp in good condition if they haven't got it in their collection.
Same as always, Desirability, condition and rarity will all determine the value. You might find that one or two stamps in the collection are worth more than all the others put together. Whether that is worth your time to go through them I am not sure.
I have a large collection that I inherited. I can't be bothered to learn... colour varieties, perforation varieties, how to spot a fake, how to grade a stamp, which stamps are worth holding on to etc. so they just sit in a box taking up space. Anything else, e.g. putting them in an album, cataloging, mounting them, taking them off the envelopes, is just going to cost me time and money with little hope of getting anything in return.
This is a timely warning to all those with coin collections. Dump all the crappy low value coins. Only keep the high value coins. Because when you pass it on, if you give them 20 albums full of crap coins and one album with expensive ones then either a dealer or a rubbish bin is going to get the lot for nothing.
Stamp collecting was popular when letters were popular, email has killed the hobby (That and the post offices of the world churning out hundreds of 'commemoratives')
Phonecard collecting was popular when public phone boxes were necessary, mobile phones have killed the hobby (That and the Telecom companies of the world churning out hundreds of 'commemoratives')
Coins were popular when high street shopping was popular, credit cards and internet transactions have killed the hobby (That and the Mints of the world churning out hundreds of 'commemoratives')