Matchday attendances would probably rise next season IF they start winning.
As for the jobs, it's like any business losing money, or needing to cut back, they will have parts of the business that they think are good to have but aren't paying for themselves, and they'll simply go. For instance, you might have some community outreach workers doing football stuff with kids - not making any profit, but a good thing to do. They might go.
You might also have a corporate hospitality team, and in anticipation of losing some corporate clients, you'll cut back.
You might also have a team of groundsmen (let's say 10) and you'll reduce that to 7 and tell the rest of the lads that they are going to have work harder still. You might soften the blow with a small pay rise, or you might simply just choose not to take quite as much care of the pitch.
You'll cut back on 3 people in the ticket office and have just 2.
There's a lot of ways of looking at it - good and bad. One view is that everybody MUST be needed, which is why they are employed. The other view is that no business is 100% optimised, and so this is a good time to start some optimisation.
It's also an exercise in making the books look better prior to sale - you can get away laying off 10 maintenance guys who look after the ground, and let the stadium deteriorate for 2 years - you probably won't see any problems. But lack of maintenance will hit home a few years down the line when the next owner has the problem to deal with.
Imagine this scenario - you're a painter and decorator and you have 3 lads working for you. You lose a contract and can now only afford to keep two of them. They are all equally good, but you simply cannot pay all three any more. There's nothing you can do other than ask them all to take a pay cut or get rid of one. It's cruel and often unfair.
This is another common problem too...
A really good guy is working in the PR department, does a great job, and is sent to the Maintenance department to help to get them organised in in good shape.
Suddenly the business takes a bad turn, and the accountants notice that the PR department is in good shape, but Mainenance is a mess and losing money. They close the Maintenance department and a really good guy loses his job because he was in the wrong department at the wrong time, even though he was exceptionally talented. Happens ALL the time.
Another thing about football clubs too - when a club is relegated it affect local businesses AND affects international trade too. Sounds very dramatic but it's true. All those pubs, and chip shops relying on matchday trade lose business. Even if attendances stay the same, they are likely to attract less away support, and have fewer cup games. It can kill off some local businesses. Then we get onto international trade.... let's say you're a business based in Blackburn. When you travel abroad and Blackburn Rovers are in the PL, the perception of Blackburn is that it's a larger town or city. It's 'on the map' as they say. When they get relegated and you're doing business, they haven't heard of Blackburn, and it's perceived as less prestigious. It can make a real difference in the perception of your business and you size, or it can be the difference between a firm chosing to open a new UK office in Southampton or Bristol. That's the power of PL for you.
Of course there's the counter to that - that a club is being promoted and might create some new jobs and boost local business etc.