Adkins was dismissed at Southampton last month despite back-to-back promotions and steering the club away from the relegation zone in their first season back in the Premier League.
McDermott was axed from Reading after Villa's 2-1 win over the Royals last weekend, despite having led the club to promotion from the Championship last year.
Lambert feels both men had produced good enough results on the pitch to stay in their jobs, but believes other factors have been taken into consideration.
"You never like to see anyone lose their job. People used to say it's a results business. It's not really anymore," said Lambert.
"If people don't like your face, or like what you are doing...
"Brian took Reading up, made them all the money and then loses his job.
"If you are telling me someone gets you out of the Championship and makes your club millions and then seven months later he loses his job, it doesn't bode well.
"It's the same with Nigel at Southampton. It doesn't really have to be based on results anymore.
"They are in an absolutely healthier position than they were two years and he has contributed a massive part to that."
Villa take on QPR on Saturday knowing a victory ould push the big-spending Londoners closer to relegation.
Harry Redknapp's position at Loftus Road seems secure enough after presiding over an upturn in form that has given the club hope of beating the drop, but Lambert would approach the match in exactly the same way even if that were not the case.
"You've got to be ruthless but you also know how other people feel because you know what it is like yourself," he said.
"Harry Redknapp is a brilliant manager, a good guy, but we have to win for our own sake."
Reflecting on the unique pressures of being a manager, he added: "Football is like that. You just never know what is around the corner. You just have to focus on your job and let other people decide that.
"You've just got to handle the pressure. It is not something I lie and worry about every night.
"You do the best you can do and what happens, happens."
Villa go into tomorrow's game full of confidence after a run of improved performances rekindled hopes of prolonging their stay in the top flight.
"It's a big game, so was last week," Lambert said.
"It's the same pressure, but I can see the lads are playing well and with a lot of confidence.
"We know only one way to play, is go and try and win. We will have a brilliant crowd tomorrow which will be right behind us.
"They will drive us on and the onus is on the home team to make the running."
Lambert has no fresh injury worries but midfielder Fabian Delph is again ruled out through suspension after picking up 10 bookings.
I think Lambert is spot on here. One look at the league table tells you that there is no such thing as 'Mid-table security' at this stage of the season this year. Whereas in previous years the bottom three much like the top three were pretty much confirmed at Christmas, this season any one of 8 or 9 teams could easily get drawn into the mix based on recent form and Reading or Southamptons form hasn't been any worse than a good many in the lower half of the table prior to the sackings. Recent history also confirms that 9 out of 10 sackings in this situation have resulted in the team being relegated under a replacement manager. If this is purely about making sound financial decisions and you convert this into business terms it means that the owner has chosen to adopt the weakest business model available in the hope that he will be the one man to reverse an established trend. Between now and the end of the season every team will play the same number of games knowing that they need the most points available and at the end of the day whether they stay or go will be down to grit and determination. Given that I live in London and I heard the bottle drop out of Anton Zingarevichs arse from here I'd say that's what's missing from the boardroom not the team.- onceavillain...